Backyards have become more than just open space—they’re evolving into extensions of the home. For many California homeowners, the decision to enhance that space comes down to two popular options: building an Accessory Dwelling Unit (ADU) or adding a pool house. While both can boost property value and improve day-to-day living, they serve very different purposes.

ADU vs Pool House: Which Should You Build?

An ADU provides fully functional living space that can be used for family, guests, or even rented out for additional income. A pool house, on the other hand, is typically a seasonal amenity built to support recreation and entertainment. The right choice for your property depends on how you plan to use the space, your budget, and your long-term goals.

In this guide, we’ll explore the differences between ADUs and pool houses to help you make an informed decision about which one is the better fit for your home and lifestyle.

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a secondary housing structure built on the same lot as a primary residence. It’s a self-contained living space with its own entrance, kitchen, bathroom, and sleeping area.

ADUs can take various forms:

• Detached ADU – A completely separate unit in the backyard.
  
• Attached ADU – An addition to the main house that shares one wall.
  
• Garage Conversion ADU – A renovated garage turned into living space.
  
• Junior ADU (JADU) – A smaller unit (usually under 500 sq ft) built within the existing home.
  

ADUs are often used to house extended family members, provide rental income, or serve as a guest suite or home office. California has been particularly supportive of ADUs in recent years, passing state laws that simplify permitting and reduce restrictions to encourage more housing solutions.

What Is a Pool House?

A pool house is a backyard structure designed to support recreational activities, especially if you have a swimming pool. It typically includes:

• A bathroom or changing area
  
• A small kitchenette or wet bar
  
• A lounge or seating area
  
• Storage space for pool equipment
  

Unlike ADUs, most pool houses aren’t built to be permanent living spaces. They generally don’t include full kitchens or meet all the residential code requirements for housing. Their primary function is to support outdoor living and make the pool area more comfortable and convenient for guests and family.

ADU vs Pool House: A Detailed Comparison

Choosing between an ADU and a pool house often depends on your long-term goals, how you use your property, and your available budget. Let’s compare both based on key factors:

1. Functionality and Usage

ADU:

• Ideal for long-term living.
  
• Suitable for renting to tenants, housing elderly parents, or offering guests a private stay.
  
• Can also be used as a dedicated office, studio, or workshop.
  

Pool House:

• Best for short-term or day use during summer and warmer months.
  
• Primarily serves as a recreational or entertainment space.
  
• Doesn’t usually meet codes for permanent living.
  

If your goal is to create a flexible space that can adapt to various needs over time, an ADU offers much more utility.

2. Cost to Build

Construction costs will vary based on size, finishes, and location, but generally:

• ADUs cost more to build due to the complexity of plumbing, electrical work, insulation, and meeting residential building codes.
  
• Pool houses can cost significantly less, especially if they are simple structures without HVAC or kitchens.
  

However, while the upfront cost of a pool house is typically lower, it also doesn’t generate income or significantly increase long-term property value the way an ADU can.

3. Permit and Zoning Regulations

ADUs:

• Heavily regulated but supported by California law.
  
• Require specific permits and inspections.
  
• Subject to square footage limitations, setback rules, and sometimes impact fees (though many of these have been reduced or waived in California).
  

Pool Houses:

• Often easier to permit because they’re not considered livable dwellings.
  
• Fewer regulations, especially if it doesn’t include plumbing or HVAC.
  

For homeowners concerned about navigating regulations, working with experienced ADU builders like Nestadu can make the process far more manageable.

4. ROI and Property Value

An ADU has clear potential to add substantial value to your home:

• Rental income: Long-term tenants or short-term vacation rentals can offer a steady return.
  
• Increased resale value: Homes with permitted ADUs are often more attractive to buyers.
  
• Multigenerational appeal: Families looking for housing for aging parents or adult children are drawn to homes with built-in solutions.
  

A pool house may improve lifestyle and curb appeal but won’t deliver the same return unless part of a luxury property package. In many markets, a pool can even be seen as a liability, depending on maintenance and safety concerns.

5. Year-Round Use

ADUs are designed for year-round habitation. They’re fully insulated, heated, and cooled, and include all the amenities needed for permanent living.

Pool houses, by contrast, tend to be seasonal. Unless built with extensive insulation and HVAC systems (which increases cost), their use is mostly limited to warmer months.

When a Pool House Might Be the Right Choice

There are cases where a pool house can be a great addition, especially when lifestyle and recreation take priority over income or space needs.

Consider building a pool house if:

• You frequently host backyard gatherings or parties.
  
• You already have a pool and need a supporting space nearby.
  
• You want a designated area for guests to change, rest, or grab a drink.
  
• You’re not interested in rental income or long-term living space.
  

Pool houses can significantly improve the flow of outdoor entertaining, especially in warmer parts of California.

When an ADU Makes More Sense

For most homeowners looking to add meaningful functionality and value to their property, an ADU is the better long-term investment.

You might want to build an ADU if:

• You need housing for aging parents, adult children, or guests.
  
• You want to generate rental income in a high-demand market.
  
• You’re looking for a home office, creative studio, or hobby space with privacy.
  
• You plan to age in place and may downsize from the main house one day.
  

ADUs offer flexibility that adapts to your life stages—something a pool house simply can’t match.

Final Thoughts: Choosing What’s Right for You

There’s no one-size-fits-all answer when deciding between an ADU and a pool house. The right choice depends on how you live, what your property allows, and what your goals are for the next 5–10 years.

If you’re thinking long-term about space flexibility, rental income, or adding housing for family, an ADU often offers the better return. On the other hand, if your property is already designed around outdoor living and you want to support that lifestyle, a pool house can be a worthwhile upgrade.