Adding a Whole New Bathroom to Your House? Here’s What it’ll Cost


When you have a full house, getting uninterrupted access to the bathroom can feel like snagging dinner reservations to the most exclusive restaurant in town. On days when your one bathroom home just doesn’t cut it, many of us dream of the elusive bathroom addition with privacy for everyone.

The only challenge? Adding a new bathroom is pricey. But in the right home, the addition will not only improve your quality of life — it will also make the property appeal to a whole different pool of buyers when you eventually decide to sell it.

“If you only have one bath and you can add to make two, that’s a huge selling feature,” says Janet Anderson, one of Tracy, California’s top real estate agents.

To help you do the math, we’re breaking down the major costs and considerations associated with adding a new bathroom. This guide includes:

  • A comprehensive cost overview from expert sources across the web
  • Major cost influencers to consider
  • A cost breakdown by component
  • A real-life estimate from an expert contractor
  • The value of adding a full bathroom
  • Tips to save on your bathroom addition

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Bathroom addition cost overview

The cost of adding a bathroom to your home will vary based on your existing space, the location of the addition, the overall size of the room, and the quality of the features. Here’s how a few of the web’s most trafficked renovation sites price out the project:

Source: HomeGuide
Average bath in existing space cost: $2,500-$12,500
Average bathroom in a new addition cost: $18,00-$47,000
Low and high end bath addition range: $2,500-$25,000
Methodology: With its network of professionals from across the country, HomeGuide uses vetted estimates from over 500,000 pros to help price out common renovation projects.

Source: HomeAdvisor
Average bath in existing space cost: $5,000-$35,000
Average bathroom in a new addition cost: $20,000-$50,000
Low and high end bath addition range: $5,000-$90,000
Methodology: HomeAdvisor averages out the data from 195,583 bathroom addition projects submitted by professionals and members.

Source: Badeloft USA
Average bath in existing space cost: $3,000-$5,000
Average bathroom in a new addition cost: $25,000-$30,000
Low and high end bath addition range: $3,000-$75,000
Methodology: Founded in 2009, Badeloft has over a decade of experience selling bathroom fixtures online and has spent 7 consecutive years on Houzz’s best-of list.

Major cost influencers to consider

Now that you have an idea of the bathroom addition cost spectrum, here’s how specific features of your home can dramatically impact the pricing of your project:

Proximity to existing plumbing

If your new bathroom is close to existing plumbing, whether it’s from the kitchen, laundry room, or above or below an existing bathroom, it’ll cost less overall to run the vents, plumbing, and waste into the new bathroom.

On average, hiring a plumber costs between $85-$120 an hour. The cost of labor for plumbing alone with average priced fixtures (high-end varieties may cost more to install) will range between $610-$1,180.

“If you want to add a bathroom to the furthest corner of your house, then you can expect to spend 30% of your budget on plumbing and electrical alone,” says Andrew Holmes, VP of Construction at Blockhouse Residential, an award-winning construction firm in Pittsburgh.

Nearby crawlspace

If your new bathroom space has a crawl space beneath it, the cost of plumbing and electrical work will likely go down. Alternatively, if you’re adding the bathroom above a concrete slab, you’ll have to pay extra for the labor to cut through it to run water and sewer lines.

Your foundation type

If you’re putting a new bathroom in the addition, you’ll have to include a line item for installing the foundation. Installation for the foundation can run between $4-$7 per square foot.

Installing dormers

You might be building up to add a new bathroom instead of out. In that case, you’ll need to consider the cost of adding a dormer to your home, which costs on average $115 per square foot.

Cost breakdown by component

Water, electricity, and sewage: Bathrooms projects have a trifecta of components that come with their installation. Let’s breakdown each moving part of this process to understand how it all adds up:

  • Architect fees. If you plan to use an architect for your new bathroom, employing one can cost anywhere between $2,175 and $10,459. If you go at it on your own, you’ll need to apply for permits yourself, which cost between $200 and $500, depending on where you live.
  • Pipe installation. Before installing plumbing, you’ll need to run plumbing pipes (water and sewage) to the location of your new bathroom, which can cost between $450 and $1,800 per fixture.
  • Plumbing. HomeAdvisor estimates plumbing can cost anywhere between $1,000-$10,000, depending on the layout of the bathroom, and its distance from existing plumbing.  
  • Electrical. The average electrician charges between $85-$120 an hour, and you’ll need their services to install, outlets, lighting, and fans. Additionally, you’ll need to use GFCI (ground fault circuit interrupter) outlets at $40-$60 each because the electric is close to water. HomeGuide estimates electrical wiring to cost between $2 to $4 per square foot.
  • Drywall. According to HomeAdvisor, most homeowners pay $2 per square foot for drywall installation.
  • Flooring. Installing waterproof flooring costs $1,500-$4,500 and pricing can change significantly based on the quality of flooring you choose. HomeAdvisor recommends one of these waterproof and durable choices:
    • Linoleum: $3-$5 per square foot
    • Luxury vinyl plank: $5-$10 per square foot
    • Marble: $16-$18 per square foot
    • Ceramic or porcelain Tile: $3-$15 per square foot
  • Bathtub/Shower install. Purchasing and professionally installing a bathtub or shower will cost between $800-$2,900 on average, but the cost can increase based on the quality and size of the tub or shower.
  • Toilet install. A professional toilet installation will cost between $300-$500, and you can find a standard toilet between $100-$200.
  • Additional fixtures. Depending on your bathroom design, you might include a vanity ($500-$4,000 for purchase and install), cabinets ($400-$3,000 for purchase and install), and a towel rack ($30-$100).  
  • Lighting. The cost to install lighting is included in electrical costs, but you’ll need to purchase the actual fixture, which can cost between $150 to $900.
  • Add-ons. Any specialty add-ons mean an additional line item in price. That includes:

Bathroom addition: A real-life example

We reached out to Holmes to get the scoop on a recent real-life bathroom addition. Holmes specializes in ground-up new construction and rehauling existing construction. He kindly provided an example quote for a recent bathroom addition under an existing room. Here’s a breakdown of the major costs and labor, including time and materials:

Bathroom Addition Under Existing Roof Labor Materials (Estimate) Cost
Design & Permits
(this included all permitting for the project, as well as architectural designs)
$2,700 $2,700
Site Prep $600 $600
Demolition & Temporary Support $1,230 $1,230
(to prep the area for running the plumbing, electric, & HVAC lines)
$1,800 $1,800
Foundation $2,200 $2,200
Framing $3,200 $3,200
Windows & Doors $644 Door: $104

Two Windows: $318

Siding $1,320 $6 per square foot (labor & materials)

220 sq. ft.

Drywall & Paint $1,520 $4 per square foot (labor & materials)

380 sq. ft.

Tile $900 $15 per square foot (labor & materials)

60 sq. ft.

Trim $600 Included with labor $600
Bath Finishes $890 Toilet: $200

Vanity: $500

Sink: $160

Plumbing $3,400 Included materials, plumbing to client purchased bathtub $3,400
Electric $1,300 $1,300
HVAC $2,600 $2,600
TOTAL $26,120

In this project, and in Holmes’ experience working with clients adding bathrooms, many of them aren’t aware how much installing plumbing, electric, and HVAC will drive up their budget.

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The value of adding a full bathroom

How much value an additional full bathroom will add to your home at resale depends on how many bathrooms you had to start with.

“If you’re talking about a one, one and half going to a two bath, there’s going to be huge value in that. But, if you’re going from a two bed, two bathroom, to a three bathroom, there’s going to be less value,” says Steven Mueller, a top Charlotte, North Carolina real estate agent who recently added a bathroom addition to his own home.

In Mueller’s opinion, adding an additional full bathroom to a one bathroom home can add between $20,000 to $25,000 in value. That’s partly because a home with two full bathrooms enters a new pool of buyers. He explains it like so: “I know the same people that will buy a one-bath home will buy a one-and-a-half bath, but buyers who want a two bath, they won’t look at a one-and-a-half bath.”

As for adding an additional full bath to homes that have two or more baths? “It depends on the quality,” Mueller says, “but the appraisal adjustment is between $7,500 to $10,000.”

In terms of ROI, a full bathroom remodel (costing close to $27,000) can net sellers a 60% return on their investment, according to a study by House Method.

Tips to save on your bathroom addition

Now that we have a complete break down of dollars and cents, let’s review ways you can save on a bathroom addition and appeal to buyers with your selections in order to maximize your investment:

  • Place the bathroom strategically. As previously mentioned, the closer a new bathroom is to existing plumbing, the less you’ll have to pay to extend water, sewage, and electrical lines. Building a new bathroom a floor above an existing one or close to the kitchen can reduce costs.
  • Buy a “used” tub and other secondhand fixtures. You might not be able to save on electrical or plumbing labor. However, you can purchase used and fixtures and refurbish them to reduce costs. If you have the time to spare and don’t mind browsing a little for a gem, you can end up with some great deals. The Habitat for Humanity ReStore, Craigslist, and local surplus construction warehouses often have new (or like new) fixtures including tubs, sinks and lighting.
  • Opt for luxury wood vinyl. Moisture-friendly luxury vinyl plank can be more affordable than other flooring alternative. These flooring options come in a variety of colors and finishes to cater to any bathroom, and buyers are responding to them with more interest than ever.
  • Go for a tile shower over a bathtub. If you’re torn between a tiled, open shower or a bathtub — go for the shower, advises Anderson. “Bathtubs are not trending right now. Buyers like open little walk-in showers without doors,” she shares.

Is it worth it to add a bathroom?

Adding a new bathroom won’t come cheap, but is the value added at resale enough to make the project worth it?

“I always ask my clients, if you’re going to do an improvement like that, how long are you going to stay in the property?” says Anderson. “If it’s five years or more, it could be worth the investment. But, if you don’t think you’re going to stay in the property one or two years, then really reconsider. You’re not going to receive that return back.”

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Header Image (Source: (Christian Mackie / Unsplash)

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