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A septic tank is a great wastewater solution if your home is not hooked up to the municipal wastewater system. When installing one, it is important to ensure it is high-quality to prevent leaking or contamination of your yard and high maintenance costs. Local rules or regulations may be in place, so be sure to check with your local municipality before purchasing a septic system.
The average tank installation cost is $4,500 to $9,000. Most homeowners pay around $6,100 to install a standard anaerobic system with a 1,000-gallon tank, typically suitable for a three-bedroom household. Prices vary depending on the tank size and materials used. A small system for a three-bedroom house using a plastic tank will likely cost closer to $3,000. Expect a larger system for a four- or five-bedroom house constructed of concrete or fiberglass to cost around $22,500.
|Average Cost of Septic Tank|
|National average cost||$6,100|
The septic tank size you need varies significantly, depending on the home or building size you are servicing and the amount of waste produced. The most common way to break down the tank volume needed is by the number of bedrooms in the home. Historically, this is a good indication of the tank size needed.
|Number of Bedrooms||Cost (Installed)|
|2||$1,500 - $3,000|
|3||$3,000 - $7,000|
|4||$7,000 - $12,000|
|5||$12,000 - $20,000|
A septic system for a two-bedroom house requires a minimum of a 750-gallon tank. Its cost typically ranges between $1,500 and $3,000. However, it is important to check local regulations because many municipalities require a minimum of a 1,000-gallon tank for a residential system.
The average cost of installing a 1,000-gallon septic tank is $3,000 to $7,000. The minimum size of the tank recommended for a three-bedroom house is a 1,000-gallon tank. Additionally, many local or state governments require a minimum of a 1,000-gallon tank. A 1,000-gallon tank typically handles 360 gallons of water per day. If you want to calculate your water usage, estimate your water flow, and multiply it by 1.5.
Typically, 1,200-gallon tanks cost between $7,000 and $12,000. A four-bedroom house needs a slightly larger tank. A 1,250-gallon tank is the minimum tank volume for a home of this size. This tank handles about 480 to 600 gallons per day of effluent. The cost varies significantly, depending on the tank material. Use the calculation above to estimate the water volume leaving your house.
Most homeowners pay $12,000 to $20,000 to install a five-bedroom house system. A tank up to 1,500 gallons should suffice, which comfortably handles anywhere from 600 to 900 gallons of water a day. Like the systems for a house with three or four bedrooms, a five-bedroom system cost varies by tank material and design.
There are many different types of septic systems, and each has pros, cons, and costs. Costs depend on various things, including the lot size, soil type, house size, and weather conditions. The costs below are based on a 1,000-gallon tank in a three or four-bedroom house and do not include installation.
|Type||Cost (Materials Only)|
|Gravity||$1,500 - $4,000|
|Conventional||$2,000 - $10,000|
|Anaerobic||$2,000 - $5,000|
|Chamber||$3,500 - $10,000|
|Drip Distribution||$4,000 - $10,000|
|Pressure Distribution||$5,000 - $7,000|
|Recirculating Sand Filter||$6,000 - $10,000|
|Constructed Wetland||$6,000 - $10,000|
|Community||$9,200 - $15,700*|
|Evapotranspiration||$10,000 - $15,000|
|Mound||$10,000 - $20,000|
|Aerobic||$10,000 - $20,000|
*additional costs per connection.
The average cost for an in-ground gravity system is $1,500 to $4,000. They are very simple in that they use gravity for water flow and filtration. A gravity system does not need a pump. The tank in these types of systems is very important. It should have risers-to-grade to help with maintenance and an effluent filter that filters out larger particles before the water leaves the tank. This system requires at least a gentle slope so that the water flows properly without a pump.
The typical cost for a conventional system is between $2,000 and $10,000. It is typically used at single-family homes or small businesses. It is an older design but one that works well, with a tank and then a trench that acts as a drain field. Typically, in this system, the trench is quite shallow, ranging from 18 to 30 inches, and constructed of gravel or stone. A geofabric is installed on top of the trench to allow water to enter the stone and prevent any sand or dirt from entering the clean soil. One downside to a conventional system is that the gravel and stone trenches take up a lot of space and might not work on a small lot.
An underground anaerobic system costs from $2,000 to $5,000. It is a very common option for homeowners. It is a fairly simple system that does not need additional chemicals or power. An anaerobic system uses bacteria that do not require oxygen to live to eat solid waste. The liquid waste is then piped out and distributed under the soil. As the water runs through the soil, the waste is naturally filtered out.
The average cost for an in-ground chamber system ranges from $3,500 to $10,000. A chamber system uses gravelless drain fields. This system has surged in popularity over the past few decades. Some benefits to a gravelless drain field include having a smaller carbon footprint 1, and they are easier to construct and install. They are also beneficial when there is no consistent flow of wastewater, such as for a cabin or seasonal residence.
There are typically multiple chambers across the drain field connected to the tank by pipes. Chamber systems work well in areas with good, natural soil that will easily absorb the effluent.
A typical drip distribution system costs between $4,000 and $10,000 but can be much higher, depending on how advanced the technology is. A drip distribution system is dynamic and does not require a large mound of soil. This system, consisting of drip laterals or long lengths of tubing, is installed between 6 and 12 inches underneath the soil. Using a pump, a large dose tank distributes the water in timed deliveries. This system requires a fairly large area and needs power to operate. For example, if you add an electrical component, it will increase expenses.
The average cost for an underground pressure distribution system is between $5,000 and $7,000. Pressure distribution systems only need 2 feet of distance between the bottom of the system and the water table level. This is a huge advantage for people who live in areas with high water tables. This system includes a pump chamber that pushes the water out and distributes it evenly across a distribution area. The pump can also push water uphill. As a result, there must be good control over the pump’s on/off action. These systems are slightly more expensive than a gravity system, but they overcome many barriers a gravity system 2 cannot.
Expect costs for a recirculating sand filter system to range from $6,000 to $10,000. What makes this system unique is the sand filter portion can be installed above or below ground. Liquid waste, also called effluent water, is pumped into the top of the sand filter, which is typically constructed of concrete or PVC. The waste in the water is filtered out through sand and stone layers before entering the ground. This system is ideal for lots with a high water table or areas near surface water, such as a lake or river.
The average cost for a constructed wetland system is $6,000 to $10,000. This is a unique and interesting in-ground system that resembles a wetland. The effluent goes from the tank into what is called a wetland cell. Wetland cells are typically constructed of a liner, gravel, sand, and wetland plants. The plants must be chosen carefully because they will always be wet. The water flows into the wetland cell, and the plants, sand, and gravel filter out the waste. The water is then distributed into a drain field. This system can use gravity or a pump.
An average cost for a conventional in-ground system for a community is between $9,200 and $15,700. Then, there is an additional cost per home or connection added to the system, which typically ranges from $3,400 to $5,100 per added connection. Sometimes called a cluster system, a community system is decentralized, meaning it does not just serve one household. Typically, a community system serves at least two buildings. These are fairly common in rural subdivisions where there is a lot of space. These systems can be cost-effective and very efficient. The cost of a community system varies significantly because it depends on the type of system installed and the number of buildings or homes included in the system.
The cost of an underground evapotranspiration system is usually $10,000 to $15,000. This unique system has an interesting design, where water is put into an open-air tank, and the water evaporates. The tank is lined with a durable water-tight material so that no water leaks into the soil. With this system, the water does not enter the soil at all. Evapotranspiration systems need to be installed in the right climate. It must be hot, have a lot of sun, and be in an arid climate. If there is too much rain or snow, the system can fail.
An above-ground septic system ranges from $10,000 to $20,000. They are a unique design intended when the depth of the soil or bedrock is shallow, or the groundwater is high. They have a sand mound constructed in the area of the septic system. A pump pushes wastewater from the tank into the mound in doses. Then, the sand filters out the water before it enters the soil and groundwater. This design needs a lot of space to build. For a standard three-bedroom home, the mound will likely be 200 feet long. For larger homes, an additional 30 feet of length is added per bedroom. It takes up a lot of space, but it is beneficial if you have shallow bedrock or high groundwater.
The average cost for an underground aerobic system is between $10,000 and $20,000. This is also a popular system among homeowners. It utilizes bacteria that need oxygen to survive to eat solid waste. Due to this, the system pumps oxygen into the tank to activate the bacteria. These systems are more expensive to install and maintain but work well where other systems might struggle. These systems work on small lots in areas where the soil conditions are not conducive to other systems and where the groundwater table is too high to utilize other systems. It is also a good option if your home is located near a body of water.
Septic tanks come in different capacities based on how many gallons of water they hold. Average prices range from $720 to $10,000. The size of your house is the biggest factor in determining what capacity you need. The larger the house, the more bathrooms and connections needed to maintain a clean and healthy environment. Below are the most common tank capacities and the associated costs of buying each tank. Keep in mind that each capacity comes in concrete, plastic, or fiberglass 3.
|Capacity||Cost (Materials Only)|
|750 Gallons||$720 - $1,200|
|1,000 Gallons||$800 - $2,000|
|1,200 Gallons||$1,200 - $2,000|
|1,500 Gallons||$1,300 - $2,500|
|2,000 Gallons||$2,500 - $4,000|
|2,500 Gallons||$3,000 - $4,500|
|5,000 Gallons||$5,000 - $10,000|
A 750-gallon tank costs $720 to $1,200. This capacity is ideal for small townhomes or single-family residences with two bedrooms. Most will only have one or two toilets connected to the system. Many 750-gallon tanks are plastic and installed above ground, but they can be used for underground systems.
Most homeowners pay $800 to $2,000 for a 1,000-gallon tank. This capacity suits a three- or four-bedroom home with two or three bathrooms. Plastic and precast concrete are common materials for 1,000-gallon tanks, usually used for conventional above or below ground systems. The average family home typically has a 1,000-gallon tank.
The average cost of a 1,200-gallon tank is $1,200 to $2,000, designed for homes with four or five bedrooms. Many 1,200-gallon tank systems are hooked up to three or four bathrooms. Alternative or engineered systems installed underground with a new drain field hold around 1,200-gallons.
A 1,500-gallon tank costs $1,300 to $2,500. This capacity is reserved for a large five- to seven-bedroom house, usually upwards of 3,000 sq.ft. There may be four, five, or even six bathrooms hooked up to the system. Fiberglass and concrete are used more commonly as the capacity goes up, but plenty of plastic 1,500-gallon tanks are available.
Expect to pay $2,500 to $4,000 for a 2,000-gallon tank. It can serve a small apartment or duplex with about 14 residents. Precast concrete is the preferred material for a long-lasting 2,000-gallon tank, which may be used by several people at the same time. Many of these larger tanks will be installed underground with a set drainage field.
If you need a 2,500-gallon tank, plan on paying $3,000 to $4,500. Small apartment buildings usually use this capacity for underground systems, with precast and plastic options readily available. The larger the tank is in size, the more labor involved to make sure it fits into place and has the proper support around it.
The average cost of a 5,000-gallon tank is $5,000 to $10,000, usually reserved for apartment buildings and community tanks. The sheer size of these tanks makes them an uncommon choice for the average homeowner unless they live in a sprawling property or farm where they want to store significant water and reuse it wherever possible by separating potable and non-potable water.
There are several different materials for septic tanks. Each material has benefits. Some are more appropriate for different soil types, climates, or uses. They all do the same job, but there is a cost difference among them. The costs below are for a 1,000-gallon tank, which typically serves a standard three-bedroom home.
|Tank Material||Costs (Materials Only)|
|Concrete||$800 - $1,250|
|Plastic||$830 - $1,400|
|Fiberglass||$1,600 - $2,000|
The average cost for a 1,000-gallon concrete tank is $800 to $1,250. Concrete tanks are very popular and the most common material used for tanks. They are durable and have a long life when made of high-quality materials and are constructed well. A good concrete tank can have a life of over 20 years. A concrete tank is very heavy, so big equipment is needed for installation. Other price factors impact the cost, depending on if it is precast or reinforced with rebar.
The typical cost of a plastic tank is between $830 and $1,400. Plastic tanks are more durable than you might think. They do not typically crack, but they can break if soil conditions change or shift. Plastic tanks are much lighter than their concrete counterparts and are typically less expensive to install. While the cost of the tank is similar, the installation costs vary greatly between a plastic tank and other heavier materials.
The typical cost for a 1,000-gallon fiberglass tank is $1,600 to $2,000. Fiberglass has many unique benefits. It is not a porous material, so there is very little chance algae will grow on the tank. It also is very sturdy and does not deteriorate underground. Like plastic tanks, fiberglass tanks are lighter than concrete or steel, so they are cheaper to install. There is also no chance of fiberglass cracking, which could happen to concrete.
Installing a septic system can be a lot of work, depending on the system type. It is an extremely technical project that should be carried out by a professional contractor. Not only do all connections need to be made perfectly to ensure the system does not leak, but the grade and depth of the components are also very precise.
Hiring a contractor for the project ranges between $1,500 and $4,000. This cost includes the system design, filing permits, and excavating and installing the system. For a contractor to do the design, it usually costs between $600 and $800. An hourly rate for a contractor varies based on the location, costing between $150 and $200 per hour. While the total project cost changes based on the system type, the hourly rate is pretty standard and should not change. A typical installation job should take two to five days or 16 to 40 hours.
The installation has several phases. First, the contractor completes an inspection to determine the scope of the design and if any soil tests are needed. The contractor then designs the system and applies for the permits. After this, excavation occurs. Next, it is time for the system installation. Once the installation is done, an inspector needs to approve it before filling in the soil and finishing the project.
It’s normal for pieces of a septic system to age and wear over time. System maintenance is usually cheaper than installing a new system because design and excavation are already done. Additionally, most systems have fairly independent pieces that are easy to replace, such as tank lids or filters.
Signs that your tank needs to be replaced include noticeable cracks or damage, unusually strong smells of sewage, standing water, slow sink/shower draining and toilet flushing, patchy grass, or contamination in nearby water sources. Remember, the average lifespan of this system is 20 to 30 years. If yours is several decades old, it may need to be replaced. If you have increased your house size substantially and added new bathrooms, you may need a bigger tank. The average tank removal cost is $5,000 to $6,000.
You can replace the tank baffle ($25 to $45), tank lid ($30 to $65), and tank filter ($230 to $280). If the tank pump fails, this is a bigger expense, typically between $500 and $1,200. Replacing the drain field is more expensive, costing between $3,500 and $11,000, while replacing a damaged 1,000-gallon concrete tank costs around $800 to $1,250. Hiring a plumber or specialist for the replacement is usually between $45 and $200 per hour. The hourly rate may vary based on area, but it should be fairly consistent for any type of septic installation or repair.
A septic tank inspection is most commonly done when buying a home and usually costs $300 to $600, with many inspectors charging based on the size of the tank and the scope of the inspection. This inspection evaluates the age, condition, and pumping power of the tank to ensure it is working optimally. Homeowners can opt for tank inspections every three to five years to ensure that everything is fine with their systems and that no performance issues or damage needs to be addressed.
Home inspectors do a visual inspection of the tank. They ask several questions about the age of the house and the date of the last inspection. Inspectors turn on all the taps and flush every toilet to check the water pressure and draining. They need to check the drain field to look for standing water or a cesspool.
In a full inspection, inspectors take off the tank cover to look at the water level and whether it changes when more water comes in. Sometimes inspectors use a dye test, putting special coloring into the draining water to see how much filters into the tank. Then the tank is pumped, and the inspector checks for any absorption backflow. By looking for absorption issues or backages, they can see if anything needs to be fixed.
Installing a drain field, also known as a leach field, costs $3,500 to $11,000. The drain field is an important part of the system that carries the wastewater back into the soil after it filters through the tank. Drain fields are typically connected to the tank by perforated pipes running 2 to 4 feet underground. These pipes carry the water into the soil, where it drains out beneath the grass. When installing a drain field, a specialist will look out for the surrounding soil environment to ensure the ground can handle the influx of wastewater. Both installers and homeowners must monitor for signs of drain field clogging or flooding. A swampy, soggy area of the yard or a strong sewage odor can indicate issues with a drain field, which could cost $2,000 to $10,000 to remediate.
A tank riser is a pipe installed on the top of a ank to give you access to the tank at ground level. This makes your system more accessible and makes maintenance and repairs cheaper, faster, and easier. The average plastic or concrete riser cost ranges from $300 to $600, with plastic being lighter and slightly easier to use. Concrete risers are a little more expensive toward the higher end of the range, but they are very durable and can end up saving money in the long run by creating an access point to your tank that is at grade.
|Plastic||$300 - $400|
|Concrete||$350 - $600|
Sewer pipes in septic systems are slightly different from the typical sewer pipe. They are a different size and usually are a minimum of 4 inches in diameter. These pipes have protection around them, such as baffles or sanitary tees typically constructed of concrete, fiberglass, or plastic, and need to be acid-resistant. The most common materials for sewer pipes for these systems are PVC and cast iron. The cost depends on the pipe length and location. The material cost of the pipe is between $100 and $240 per linear foot of material to replace or install a sewer pipe. The cost for a plumber to do the installation or repair is typically between $45 and $200 per hour.
While the distribution box might not seem like a major component in the septic system, it is one of the most important pieces. The distribution box is where the effluent flows through to get to the drain field. It is the connector between the tank and the drain field. If the distribution box is damaged or not functioning, it can cause the entire system to fail.
A distribution box is not very expensive, usually between $50 and $100 for a plastic distribution box. Concrete is more expensive because the boxes are heavier and have to be precast or cast in place. The cost of a concrete distribution box is usually between $600 and $650.
It may be necessary to clear some land and do preparation work on the site before installing a septic system. Land clearing prep work costs between $1,600 and $8,000, with prices varying based on the size of the land and the scope of the work. This is important because even the most advanced system won’t work well if the soil cannot support it. Land preparations usually start with soil testing, with the average perc test for septic costs around $600 to $800. This test reveals how long it takes for the soil to drain and will help your installer understand the best place to install your system and which type of tank is most suited to your property.
Once you settle on the right spot to install the system, it’s time to excavate the area for the drain field. Most contractors include this in their installation costs because the elevation, slope, and system depth are all extremely specific. After installing the system, your contractor cleans up the surrounding landscaping to protect and secure the tank.
Mobile homes connect to these systems the same way as any other building or home. The major difference when designing, installing, or connecting a system to a mobile home is that the placement is critical. A tank cannot withstand the weight of the home if you move it. As a result, the tank and septic system needs to be in a location where the home will not be hauled over it.
The most common system type used for mobile homes is a conventional one with a standard drain field. The average cost to install and connect a system like this to a mobile home is typically between $3,000 and $5,000.
Installing a septic system for an RV costs $2,000 to $3,000. Families on an RV road trip often appreciate their own system so they can use the toilet, sink, and shower while traveling. Many modern RVs come with them, but you will have to check with the make and model. You can upgrade the system if you are refurbishing an older RV. An RV plumbing system includes tanks that contain wastewater from the sink, shower, and toilet until it can be disposed of at a sewer connection, which is normally available at campgrounds.
While a septic system is a simple onsite sewage solution that collects wastewater for basic treatment, a cesspool is a shallow underground pit for sanitary waste disposal. A septic system pumps wastewater and eventually filters it out through pipes into the soil drain field. But a cesspool simply holds the waste in place inside a concrete-lined pit. A cesspool can’t filter waste, so it eventually contaminates the nearby soil. To prevent soil contamination and enjoy a cleaner, safer system for the long term, homeowners may choose to replace a cesspool with a full septic system. To do this, expect to pay at least $4,000 to $6,000. Prices may be higher depending on the size of the cesspool, deterioration of the surrounding soil, and the requirements for the new system. The process should take just a few days, although installers must ensure the stability of the soil around the cesspool. The cesspool needs to be drained, the concrete liner removed, and then installers will work the soil accordingly. Once the soil is ready, the new system can be installed.
Converting an anaerobic system to an aerobic one costs $5,000 to $10,000. Anaerobic systems are less expensive, costing $2,000 to $5,000 as a traditional and common septic system with relatively no oxygen in the tank. Aerobic systems support bacteria that live off oxygen and help break down sewage, making them more expensive, around $10,000 to $20,000.
The advantages of converting from an anaerobic system to an aerobic one include the cleaner effluent flowing out of the system, which minimizes the chances of groundwater contamination. If you live somewhere with a high water table, an aerobic system helps prevent water pollution. The main downside is, of course, the higher installation costs. Additional maintenance is also involved, like checking the air injection and electrical systems.
The advantages of a septic tank outweigh the disadvantages for most homeowners. This project is a sizable investment, costing from $720 to $10,000, but it’s money well spent when you can dispose of waste in a safe, sanitary way. Septic systems also give homeowners independence and peace of mind knowing they can use their sinks, showers, tubs, and toilets without worrying about clogs and backups in a community sewage system.
Septic systems protect the environment by removing pollutants from surface water and replenishing groundwater. They protect your family’s health and the wider health of the community by reducing the risk of pollutant and pathogen transmission. On the downside, these systems may encounter problems, especially as they age. Damage to the tanks and other sections of the systems may require repairs. If the drain field overflows, you will also need to get that fixed. Even so, the maintenance requirements of a modern system are minimal, especially if it was properly installed by a professional.
In a way, all systems are customized to best suit your home and property. Septic system installation costs are not normally separated into prefabricated and custom, just because so many factors influence the price, even if it’s installed with a standard tank available at a building supplies store. Most projects involve a prefab tank available through the installer, who can then customize it throughout the installation process for the most effective distribution into the soil. The best type of system and any required customizations and tweaks depend greatly on your property.
Some residences can accommodate a simple above-ground tank with no problems, while others need a comprehensive in-ground installation with a new drainage field built. The best way to understand the estimated costs for your installation is to speak to a certified installer who can inspect your property, offer recommendations, and set budget expectations. Further customization, including building a new tank, can add anywhere from $500 to $10,000 to the project. It just depends on each individual property.
Septic tank maintenance is a necessary and preventive aspect of having a septic system. Like most systems in your home, some maintenance is necessary to keep everything in the proper working order. In this case, most maintenance is considered preventative. The most important maintenance task is pumping and cleaning the tank every three to five years. This is a pretty standard timeline, no matter which system you have. Cleaning costs usually range from $400 to $1,000 and include any tools and equipment the plumber or specialist may need. Most maintenance does not need any material replacements, so you will only pay if something needs replacing.
A septic system costs $3,100 to $9,600 to install while connecting to a main sewer line can be slightly more affordable, around $1,500 to $8,000. Think of this system as your own personal sewage system. A septic system treats wastewater on site, with an underground tank and pipe system on your property. If your home plumbing system is not hooked up to a septic system, it is connected to the main city sewer line. Sewage connections carry the wastewater from your home and route it underground to a city or county treatment plant.
|Sewer||$1,500 - $8,000|
|Septic||$3,100 - $9,600|
A holding tank is seen as a temporary solution for holding wastewater, costing $500 to $4,000 compared to $3,100 to $9,600 for septic systems. As the name suggests, a holding tank holds wastewater but doesn’t have a system to filter the waste. Once a holding tank reaches capacity, it must be emptied, with most requiring monthly, if not weekly, pumping.
Holding tanks are a better option for tiny homes, trailers, boats, or RVs, as they are not designed for larger family homes. Unlike a holding tank, a septic tank is a full system that filters wastewater and sends effluent out into the drain field and surrounding soil. A full septic system is more expensive but requires less maintenance and is more permanent than temporary holding tanks.
|Tye of Tank||Cost (Installed)|
|Holding||$500 - $4,000|
|Septic||$3,100 - $9,600|
A pump alarm may be necessary with some systems, such as a pressure distribution system. These alarms are triggered when the wastewater level gets extremely low. If the pump continues to run when there is no water to distribute, it can ruin the pump. A tank alarm ranges from $100 to $500.
The average cost of installing a septic system is between $3,100 and $9,600, including the system and installation. Anaerobic, gravity, and chamber systems are on the lower end of that average, usually costing $1,500 to $5,000. More expensive systems include the mound system, aerobic, and evapotranspiration and range anywhere from $10,000 to $20,000.
A 1,000-gallon tank usually costs between $800 and $2,000, but the price varies depending on the tank material. A concrete tank has the cheapest material cost, between $800 and $1,250, but it is the most expensive to transport and install because of its weight. A plastic tank is slightly more expensive, $830 to $1,400, but its weight makes it much cheaper to install, and heavy machinery is usually not needed. A fiberglass tank usually ranges between $1,600 and $2,000.
A septic system typically lasts between 15 and 40 years. This is usually determined by the quality of the tank and the drain field. A concrete tank is extremely durable. When constructed well, it is fairly indestructible and can easily last 40 years. The lifespan of a plastic tank is about 30 years. The drain field can also be a limiting factor on the age of the system. The drain field type does not affect the lifespan of the system. However, the quality of the soil and drainage is a huge factor. Not doing maintenance on the system is one way to shorten the life of any system.
The smallest area a septic system will usually fit in is a ½-acre lot. Most homeowners with small lots opt to use an aerobic system. Most systems, such as an anaerobic or chamber system, typically need at least a one-acre lot. Mound systems need the most space because the mound itself is usually a minimum of 200 feet long.
Heavy rain can cause problems for all types of systems because they can flood the drain field. If the drain field floods or the soil is saturated, the effluent septic water cannot effectively drain into the soil. This can cause major backups in the tank and even flooding.
A small septic system for a two- or three-bedroom home can handle about five loads of laundry per day. This does not include any other water being used and is based on using an old washer with a 1,000-gallon tank. The washer type is a major factor because older washers can use up to 40 gallons per wash. New energy-efficient washers usually use 12 to 15 gallons of water.
The average 1,500-gallon tank costs $1,300 to $2,500. This capacity is ideal for a large five- to seven-bedroom house around 3,000 sq.ft. or more. Homes with four, five, or six bathrooms can benefit from a 1,500-gallon tank, usually made of fiberglass or concrete, although plastic tanks are also available.