Bathtubs are a must-have feature for many homeowners. They are great for relaxing tired muscles at the end of a long day, for bathing young children, and are available in various sizes and styles to suit just about any decor. Some new models offer special features like chromatherapy, inline heaters, whirlpools, and air jets for an enhanced bathing experience. It is also recommended by most interior designers and realtors that, for resale value, you have at least one bathtub somewhere in your home.
With the wide range of different types of bathtubs on the market and the many ways they can be installed, there is also a wide range of associated costs. The national average price for installing a bathtub is $1,500 to $5,000, with the average homeowner spending around $2,750 on an installed 6-foot freestanding soaking tub with a tub filler. The lowest cost for a bathtub installation is around $800 for a 5-foot acrylic alcove tub, while the highest cost would be around $18,000 for a 6-foot stone Japanese soaking tub.
|Bathtub installation prices|
|National average cost||$2,750|
|Average range||$1,500 - $5,000|
Bathtubs come in a wide range of shapes and installation styles. They can be installed freestanding, with a deck, or as part of a shower. Each of these different configurations affects both how much the tub costs and how it is installed. Nearly all tub combinations come in various sizes, styles, and materials, so no matter which configuration best fits your needs, you can also easily find one that meets your decor.
|Configuration||Average Costs (Material Only)|
|Alcove||$200 - $1,000|
|Bathtub/Shower Combo||$300 - $2,000|
|Drop-In||$400 - $4,000|
|Undermount||$500 - $5,000|
|Freestanding||$600 - $20,000|
|Corner||$1,000 - $5,000|
|Japanese-Style||$2,000 - $20,000|
Most people are familiar with the alcove bathtub installation. This is the most common type of tub and is installed along with a shower. The tub is finished across its front, with an apron, while the back and sides fit flush against the wall. These tubs are usually 5-feet long and range from 30 to 36-inches wide. When needed primarily for showering, they are usually about 14-inches deep, but you can find alcove tubs of different sizes made for soaking, with whirlpool or air bath options. Alcove tubs cost between $200 and $1,000 on average, depending on the size, style, and material.
Any alcove tub can be made into a tub/shower combo by giving it a waterproof surrounding. You can also purchase readymade tub/shower combinations. These units are usually made of acrylic or fiberglass and come in 1 to 3 pieces. They have few seams and are easy to care for. The tub portion is almost always 60-inches long, 30-inches wide, and 14-inches deep, but there can be variations between brands. Expect to pay around $300 to $2,000 on average.
If you want a larger tub built into a deck, you have two options. The most common and least expensive way to install a tub inside a deck is with a drop-in tub. Drop-in tubs hang from their rims onto the deck. The deck is usually made of plywood then tiled. The tubs come in many sizes and shapes, including rectangles, ovals, and corner configurations. They may be made for soaking or have jets, and materials include acrylic, fiberglass, and iron. They cost between $400 and $4,000, depending on the style and features.
The second method of installing a tub into a deck is to undermount it. In this scenario, you have a plywood box for your deck with the sides and top tiled or covered in slab materials. Then the tub is installed on the underside of the deck top, exactly like an undermounted sink in a standard kitchen counter. This gives you a cleaner, more contemporary appearance. However, it is also a slightly more complex and expensive installation. These tubs range from $500 to $5,000 on average.
A freestanding bathtub is meant to be approachable from all sides. It does not need a deck or surround of any kind and can stand on the floor, a plinth, or a set of “feet.” Clawfoot tubs are an example of a freestanding tub and so are Roman, Greek, and Japanese tubs. Garden tubs are also a kind of freestanding tub, typically designed for soaking. Freestanding tubs come in many shapes, sizes, and materials, as well as styles. They can be made for soaking, come with jets, or be designed for air baths. They usually cost between $600 and $20,000.
If you need to conserve space but still want a dedicated bathtub for soaking or with jets, a corner tub helps you save room. Corner tubs extend along two walls, with usually 1 long connecting side in the front. They can be designed for a single user, or for two, with one bathing space extending along each wall. Installation is a choice between alcove-style with an apron front or undermounting into a deck. They cost between $1,000 and $5,000, depending on the size, material, and style.
Japanese-style tubs are an extension of an entire bathing culture and are entirely dedicated to relaxation and stress-relief. They are a very deep soaking tub, usually in a circle or square. In this tub, the bather does not stretch out, but sits upright with the water coming up nearly neck-high. Because of the extra depth, there is usually a seat with room for the legs to be comfortably bent. These tubs are created for soaking, but some can be fitted with jets or made as an air bath. They use many different materials and can be freestanding or designed for deck mounting using either a drop-in or undermount style. A few companies also make these with a front apron, so you could install it in an alcove. Expect to pay between $2,000 to $20,000.
Bathtubs are made from many different materials, depending on if the tub needs to be lightweight or hold heat extra well. Other materials are chosen based on aesthetics or to match a particular decor. Each distinct material has its own costs and attributes to consider.
|Material||Average Costs (Material Only)|
|Steel||$200 - $2,500|
|Acrylic||$200 - $13,750|
|Fiberglass||$300 - $4,500|
|Cast Iron||$375 - $2,500|
|Cultured Marble||$1,400 - $5,000|
|Solid Surface||$2,000 - $6,000|
|Copper||$2,000 - $6,000|
|Ceramic Tile||$5,000 - $10,000|
|Granite||$10,000 - $20,000|
Porcelain-enameled steel is one of the oldest and most common materials for bathtubs. This is a common material for alcove tubs since it holds heat well, lasts for years with little maintenance, and is not as heavy as cast iron. Some contemporary tubs are clad in a thin layer of steel on the exterior as well. In this case, since the steel is not porcelain-enameled, it requires higher maintenance to prevent fingerprints, smudges, and other blemishes. Steel tubs cost between $200 and $2,500 on average.
Acrylic is one of the most common materials for bathtubs of all varieties. It is lightweight, durable, and easy to care for. Acrylic tubs can be clawfoot, freestanding, jetted, air bath, or soaking styles, and they come in a wide variety of sizes, looks, and colors. Their only real drawback is the fact that acrylic does not hold heat particularly well. It is also not as long-lasting as steel or cast iron tubs. Prices range from $200 to $13,750.
Fiberglass is a good option for a lightweight, durable tub that has reasonable heat retention. Fiberglass is commonly used alongside acrylic in some larger soaking tubs, and it may also be used in tub/shower combinations as well as alcove tubs. Fiberglass tubs come in several colors, styles, and sizes. They are fairly easy to care for. But they are not quite as common, so styles can be more limited than acrylic. They cost between $300 and $4,500.
Porcelain-enameled cast iron is another very common tub. Like steel, cast iron is one of the oldest materials for tubs still in use today. Porcelain-enameled cast iron is durable, long-lasting, easy to care for, and holds heat very well. These tubs are most commonly alcove or clawfoot in their configuration, but you can find some drop-in and different freestanding varieties as well. They cost between $375 and $2,500 on average, depending on the choices.
If you are looking for a unique color, appearance, or tub size, consider having a cultured marble bathtub made. These tubs are almost always poured to order, which gives you the ability to exactly specify coloring, size, and shape. Cultured marble tubs can be an alcove, corner, or drop-in style, with a few companies also making freestanding units in limited styles and sizes. The tub is given a gel coating as part of its production, making it smooth and easy-to-clean. This gel coating can be reapplied for long-lasting durability. Expect to pay around $1,400 to $5,000.
Solid surface is a relative newcomer to the bathtub field. They use the same material that solid surface countertops like Corian are made from. The color goes all the way through the tub, so scratches and surface stains are easily buffed out. These tubs are mostly freestanding and available in a large array of contemporary colors and styles. They are very durable and hold heat better than acrylic, so they are growing in popularity. They cost between $2,000 and $6,000.
If you want to make a statement with your bathroom decor, consider a copper bathtub. Copper bathtubs are predominately freestanding. They may be made of solid copper or just have copper plating over a cheaper corel. These bathtubs are durable too, as this material is naturally resistant to dents and scratches. Copper is a “living finish,” meaning it darkens and dulls when not frequently touched, yet it remains bright in places that are often handled. As such, these tubs require special care to keep them looking their best. Prices typically range from $2,000 to $6,000.
If you want a unique, one-of-a-kind bathtub, build a ceramic tub. To do this, start with a frame made of cement backer board. Then tile, using your choices of colors, styles, and shapes. You can add jets if you desire or make it a soaking tub. These tubs can be alcove or freestanding, depending on your design. They cost between $5,000 and $10,000, depending on the tile choice, size, and configuration.
Natural stone bathtubs, such as granite, are incredibly beautiful, unique additions to any bathroom. They are usually carved from a single block of stone, and many of them are hand-cut and polished. They can be contemporary-looking but can also be very rustic if you choose an unfinished exterior. These tubs are very heavy and need a reinforced subfloor. They also require frequent maintenance to prevent stains and etching. Prices range from $10,000 to $20,000.
There are many ways to install a bathtub. If you are designing a tub/shower combination, then your tub will need a surround. The surround is what helps create a waterproof covering on the walls above the tub. They are frequently tile or the same material as the tub when you purchase both as a set. Here is a cost comparison of some of the most common materials used for tub surrounds, assuming a size of 60 inches x 30 inches x 72 inches:
|Surround Material||Average Cost (Material Only)|
|Tile||$120 - $6,000|
|Composite||$250 - $2,000|
|Acrylic||$300 - $700|
|Fiberglass||$400 - $1,200|
|Natural Stone||$2,400 - $24,000|
|Solid Surface||$6,000 - $12,000|
|Quartz||$6,000 - $12,000|
Tile is the most popular choice for tub surrounds because it is waterproof, stain-resistant, and easy to clean. If you want to create a custom look for your bathroom, use a tile surround with an alcove tub. Nearly any kind of tile can be used for this. Ceramic, porcelain, and glass are the most common, but natural stone works as well. The cost and maintenance of the surround vary depending on the type of tile. The average cost for a 60-square-foot surround is $120 to $6,000, depending on the tile you choose.
Fully formed tub surrounds made out of three pieces are designed to be installed directly to your walls. Composite tub surrounds are one material that meets this criteria. These composites are usually white but may be embossed to look like real tile. Grab bars are a frequent option. Composite materials can be made of a range of substances, including acrylic and fiberglass as well as some stone material. These surrounds cost between $250 and $2,000 on average.
If you have an acrylic tub, you may want to match it with an acrylic surround. These surrounds are made of the same easy-to-care-for material as your tub. They nail to the wall studs and may have grab bars included. They come in several colors, though white is the most common, and have either one or three pieces for easy installation. Costs range from $300 to $700.
Fiberglass tub surrounds can be a good match for fiberglass tubs. They can also be a good way of dressing up other tubs with interesting surrounds. Fiberglass surrounds can be made to look like tile, yet they lack the grout joints that make tile hard to clean. They come in several colors and may have built-in grab bars and soap dishes. They are mostly designed to nail to the wall studs, but some can be simply glued down. Costs vary between $400 and $1,200.
If you want to create a unique and elegant tub surround, consider natural stone slabs. These are large 2 cm or 3 cm thick slabs that are cut to fit your exact tub dimensions. Natural stone slabs may be marble or granite and come in a wide range of colors and styles. Keep in mind that natural stone requires a lot of care to keep it from staining. Depending on the stone, slabs have a wide range of costs, between $2,400 and $24,000.
Solid surface slabs make an excellent low-maintenance tub surround. This is the same material used in solid surface countertops. They come in an incredible range of colors and styles. Because the edges are heat-sealed together during installation, there are no seams, making this a very watertight and easy-to-clean surround. Prices range from $6,000 to $12,000, depending on the color and style of the material.
Quartz slabs are another material that can be used to create a tub surround. They are very low-maintenance, not requiring any special care or cleaners. Quartz slabs come in a wide range of colors and styles and can mimic the look of other natural stones. Some quartz slabs feature brilliant colors, such as deep blue and orange. A quartz surround costs between $6,000 and $12,000 on average.
Depending on how they are used, bathtubs are generally sorted into several categories, such as general-purpose, soaking, walk-in, and whirlpool. Each of these tubs has its own characteristics as well as price range. There can also be overlap between them, such as a whirlpool tub with air jets or a walk-in tub also designed for soaking. In addition, installation styles impact the final project costs.
|Tub Purpose||Average Cost (Material Only)|
|General-Purpose||$200 - $800|
|Soaking||$1,000 - $12,000|
|Hot Tub||$1,000 - $40,000|
|Whirlpool||$1,500 - $10,000|
|Air Bath||$1,500 - $10,000|
|Walk-In||$2,500 - $20,000|
General-purpose bathtubs are the standard bathtubs that everyone is familiar with. They are generally shallow, about 14 inches on average, so they are not the best tubs for adults who want to bathe regularly. They may be made of almost any material and are usually installed with a shower. They cost between $200 and $800 on average.
Soaking tubs are deeper than general-purpose tubs and allow you to immerse yourself entirely. Freestanding clawfoot and slipper tubs are in this category. Japanese soaking tubs are as well, allowing you to sit and have water up to your shoulders. Most soaking tubs are big enough to stretch out in, and many have reclining backs for extra comfort. Expect to pay around $1,000 to $12,000, depending on the material and size.
Hot tubs are not technically bathtubs, but they fall into a similar category. They are used for hot water relaxation, rather than for bathing. They are also believed to offer other health benefits, like pain relief, muscle relaxation, or sleep improvement, among other things. They come in many different styles and materials, with some designed to hold many people. Hot tubs are usually installed outside the house, but some can be installed inside, assuming proper flooring and support. They cost between $1,000 and $40,000 on average.
Whirlpool tubs are designed to give you a spa-like therapeutic experience. These are jetted tubs that circulate the water and air to provide a massaging burst at every jet. Whirlpool tubs have arrays of jets that are either positionable or fixed. They come in many shapes and sizes, and some offer speciality features like lights or lumbar support. Prices range from $1,500 to $10,000, depending on the size, style, and brand.
An air bath is a soaking tub with a ring of small holes either around the perimeter or around the base. Pressurized air is sent through these holes, which gives a more gentle massage. Standard jetted tubs are not recommended for people with diabetes or other health conditions because their moving water carries a lot of force. Air baths, however, can be used in their place because their gentleness helps stimulate circulation without the danger of bruising. Expect to pay between $1,500 and $10,000, depending on the size and style.
A walk-in tub is designed for people who have mobility restrictions and cannot climb into a standard tub. Walk-in tubs have a door that allows people to walk into the tub instead of stepping over the rim. A tight seal on this door keeps the water inside once closed. The tub is designed to start filling when the occupant is seated inside and must completely drain before the door can be opened. They may have whirlpool or air bath options, depending on the brand. They usually cost between $2,500 and $20,000.
Bathtubs come in a full range of sizes, from small “birthday” baths that are just 3-feet long to oversized jetted tubs meant for two that are 6½-feet long. In addition to the length, tubs also come in all different widths and depths. These vary by the type of tub installation, as well as the tub function. Below is a basic size chart to help determine which tub best fits your needs.
|Alcove||40” to 72”||30” to 36”||14” to 24”|
|Freestanding||36” to 80”||30” to 46”||14” to 36”|
|Jetted/Air Bath||60” to 80”||30” to 40”||24” to 36”|
|Undermount||60” to 72”||36” to 40”||18” to 24”|
|Drop-In||60” to 72”||36” to 40”||18” to 24”|
|Walk-In||52” to 60”||30” to 32”||24” to 36”|
|Corner||60” to 72”||60” to 72”||18” to 24”|
No matter which type of bathtub you have, you need to have a way to fill it. A tub filler is a faucet that fills your bathtub. It usually has a higher number of gallons per minute than a standard faucet. Tub fillers can be deck-mounted or mounted on the side of the tub, floor-mounted, coming up from the floor and extending over the rim of the tub, or they can be wall-mounted, either as part of a shower valve setup or as a stand-alone filler. Tub fillers have a range of styles and finishes in each category, which produces a range of costs for each.
|Filler Style||Average Cost Range (Material Only)|
|Deck-Mounted||$100 - $500|
|Wall-Mounted||$200 - $500|
|Floor-Mounted||$300 - $700|
The cost to install a new bathtub is directly tied to the type of bathtub being installed. Freestanding tub installations are generally the simplest, while a whirlpool undermount installation may be the most difficult. In general, alcove installations are the most common. In this installation, the tub is secured to the subfloor and the walls using a ledger board the same length as the tub to attach it to the studs. A tub flange is installed just above the tub, and the tile or surround is installed over the flange to create a water-resistant installation.
In a deck installation, the deck is built first, using either plywood or backer board. The sides are finished, and if the tub is being dropped in, the top is finished first, then the tub is placed. If the tub is undermounted, it is attached to the top of the deck first, upside down. The entire thing is then picked up and installed into the deck together, both top and tub.
In a freestanding tub installation, the tub is simply placed and leveled. In all tub installations, the drain is assembled and attached, and the tub completely leveled and caulked in to prevent moisture accumulation.
Before any tub installation, your contractor should ensure that the subfloor is level. If not, it can put undue strain on the plumbing and cause leaking after some time.
All tubs should be installed by a licensed plumber ($45-$200 per hour). A new tub installation takes around 6 to 9 hours and costs between $270 and $1,800 in labor. To remove an existing tub, add at least an additional 3 to 4 hours to the total time and add $135 to $800 more.
Some plumbers might charge a fixed rate ($500-$1,800) for a bathtub installation, which includes the tub, flange, strainer, and overflow pipe installation, redoing the hot and tub piping in line with the new fixtures, drain pipe sizing, and connecting the waste pipe. Any additional work might be charged at an hourly rate. The exact rate is dictated by the tub type and its installation because some are simpler than others.
When installing a whirlpool tub or air bath, you may also need to hire an electrician ($40-$100 per hour) to put in new wiring, which can take 2 to 6 hours for an additional cost of $80 to $600.
Below are the average costs to install a bathtub, along with the cost of installing the drain and tub filler, for a complete installation:
|Tub Type||Average Cost to Install (Labor Only)|
|Freestanding||$500 - $1,100|
|Alcove||$750 - $1,450|
|Drop-In||$950 - $1,700|
|Undermount||$1,000 - $1,800|
|Whirlpool/Air Bath (Jetted)||$1,500 - $2,000|
Freestanding tubs are usually the simplest installations. The subfloor must be checked and reinforced if necessary, and the tub balanced and shimmed. Then, the tub is fixed into place, and the plumbing is installed for the drain and tub filler. Most freestanding tubs use a floor-mounted filler, which requires the plumbing to come up from the floor below. This has a total cost range of $500 to $1,100 for labor. With the tub and filler, this has a total cost of around $2,750 for the average acrylic tub installation.
Alcove tubs are one of the most common types of installations. The tub sits in an alcove, so that three of the tub sides are against a wall. The walls above the tub must be finished either with tile or some type of readymade surround. This type of installation is more invasive than a freestanding tub because the tub must be secured to the walls. If you plan on tiling, the installer must also secure a flange to the tub where it meets the walls for a watertight installation. This has a cost range of $750 to $1,450, depending on the tub type.
To install a drop in tub, the installer must first build a deck. The deck can be built out of plywood or backer board, depending on how it will be finished. The tub must be onsite for the deck to be built. This is because the measurements of the tub are necessary to cut the correct size opening in the top of the deck. Then, the tub can be hung, caulked into place, and plumbed. This has a cost range of $950 to $1,700, depending on the type of tub being installed.
An undermount tub also requires a deck. The difference is that the top of the deck is not installed until the tub is ready. The top of the deck is placed upside down, and the tub is installed upside down, around the deck opening. Once the epoxy cures and the tub is fully secured to the top deck, the entire deck top will be flipped, with the tub, into the rest of the deck. This can be very difficult, depending on the top material, and may require multiple people. Therefore, this installation has a cost range of $1,000 to $1,800 on average.
Jetted tubs can be installed in alcove, drop-in, undermount, or freestanding configurations. They have special plumbing, draining, and electrical requirements. The labor portion of installing a jetted tub averages between $1,500 and $2,000. This is because the tubs can be installed in such a wide range of ways. If the tub is being installed in a deck, one panel of the deck must remain movable or removable to allow continued access to the tub plumbing. Sometimes, this means that the deck will not be completely finished until the tub is in place.
The cost to install a tub surround depends largely on the type of tub surround. A readymade surround of acrylic, fiberglass, composite, or some other premade material has an installation cost of around $200 to $300 on average, making the total cost range between $450 and $2,300.
For a tile surround, the labor cost is around $3,000, including the framing of the walls, backer board installation, and tile surround, which needs to be caulked and finished. This is in addition to the cost of the materials, which are between $120 and $6,000 for the tile, making the installation costs between $3,120 and $9,000, depending on the surround type.
Tile tub surrounds are some of the most common types. To be installed, the walls need to be framed, plumbed, and covered in a water-resistant backer board, then tiled. The average fees for the labor and material costs outside of the tile average $3,000 per surround. The tile costs for the average surround range from $120 to $6,000, depending on the tile. This makes the total cost range to tile a tub surround between $3,120 and $9,000, depending on the tile.
Simply replacing a bathtub with one of the same average size and type has similar costs to a new installation, plus the costs of removing and disposing of the old tub. It is important to find a new tub of the same dimensions to make this project easier. The cost of removing the old tub is between $200 and $1,200, depending on the tub type, what it is made of, and how hard it is to remove. While installing a new tub may cost $500 to $1,800 in labor, the total labor to replace a tub is between $700 and $3,000, along with the cost of the new tub, for a total cost range of between $900 and $23,000, depending on the tub type and material.
Replacing a tub with a shower stall also has a range of costs. Shower stalls can be the same size as the old tub, or they may be larger or smaller. They can be made of many different materials and be prefabricated or custom made. Costs average between $1,000 and $9,000 to replace the average alcove bathtub with a new shower stall.
When replacing an alcove bathtub, your average cost range to replace just the tub and plumbing is around $900 to $1,200. The cost of replacing the tiles on the walls is an additional $120 to $6,000 in materials, with labor costs around $600 to $1,000. This makes the total cost of replacement of the tub and shower between $1,620 and $8,200. This assumes that, once the current tile walls are removed, the shower walls do not need significant repair due to water damage.
When replacing a prefab tub/shower combination unit, your costs to remove the unit will be around $200 to $300, cost of the new unit $300 to $2,000, and labor costs for installation another $500 to $800, making the total project cost $1,000 to $3,100.
If you are replacing a shower/tub combo made of a separate tub and a tile shower surround, your costs will be between $1,520 and $8,200 on average, depending on the type of tile and tub.
The costs of converting a walk-in shower to a tub are similar to the costs of a new tub installation, along with the removal and disposal of the current shower and framing of the walls. Expect the labor for this job to be around $4,000 total for the removal, framing, and installation of the new tub and tub surround. This is in addition to the cost of the tub and the plumbing, which ranges from $300 to $1,800 on average, depending on the type and material. The total cost to convert a current shower to a tub is between $4,300 and $5,800.
The cost to remove a bathtub is largely dependent on the tub type and material. In most cases, the labor is around $200 to $300 for removing an alcove or freestanding tub. Costs can be higher, however, if this tub is in a deck installation, made of a heavy material that must be removed from an upper floor of the house, or oversized and unwieldy. If the tub cannot be taken out through the house, it may need to be removed through a window using a crane, which further increases costs. While most tubs can be removed for $200 to $300, specialty situations can increase costs to as high as $1,000.
When installing a large whirlpool bathtub, make sure your water heater is big enough to handle the load. Ideally, the water heater should be roughly ⅔ the size of the bathtub. A new water heater costs around $1,000 on average.
If your whirlpool or air jet tub requires a separate electric circuit, you may need to upgrade your complete electric panel. This can raise the installation costs by around $2,500 on average.
If you have a current bathtub and shower surround that are in good condition but not in a color or style that is up to date, you can cover them. A Bath Fitter is a method of covering up old tubs. This is a multi-piece cover that fits over your existing bathtub and the walls around it. It is seamless and can cover up stained tile and grout or old tubs. Costs start at around $1,400 for the average bathtub installation.
On average, expect to pay around $2,750 for installing a 6-foot acrylic freestanding bathtub with a tub filler.
Building a new bathroom costs around $47,000 on average. This cost includes the framing, plumbing, and finish work of the entire room.
You can put in a medium to high-end shower stall for $8,000, including the shower pan, stall, doors, plumbing, and labor charges.
A bathtub replacement costs between $1,000 and $9,000, depending on the area, conditions, and type of bathtub and materials.
Plumbing a new bathroom is a complex project that involves proper planning, site preparation, installation of a sink, shower, and bathtub, connecting each fixture to the drainage and plumbing, and cleanup. In addition to a deep understanding of plumbing systems and techniques, you also need basic carpentry skills, especially if there is a need to modify the framing. Always use pipe sizes and types that comply with the building codes.
This project can take about 6 to 8 hours on average. If you encounter issues with water damage or the plumbing needs to run beneath the floor, it can take as long as 9 to 12 hours.
This depends on the tub. It is not unheard of for some cast iron tubs to last nearly 100 years. On the other hand, some acrylic tubs may only last 20 years. How they are installed and taken care of impact how long they last.
They do. In fact, it is usually recommended that you have a plumber install your bathtub. This is because the tub also includes a drain and tub filler, and your plumber can handle all these things at once.