In this guide, we’ll cover everything you need to know about building a pool house or poolside ADU: important distinctions, definitions, construction rules, setbacks, cost considerations, floor plan ideas, and even when it makes sense to fill in a pool to build an ADU instead. We’ll explain the real difference between a pool house and an ADU so you can choose the right approach for your property.
Pool House vs. ADU: What’s the Difference?
Many homeowners searching for a “pool house ADU” are actually deciding between building a traditional pool house or a full ADU near their pool. The difference is critical legally, financially, and for resale value.
When choosing between the two, there are a few key differences to consider. An ADU offers complete independent living facilities. It includes a full kitchen with a sink, fridge, and cooking appliances. ADUs also have a bathroom. In contrast, a traditional pool house is a non-habitable structure for accessory use. This makes the term “pool house” somewhat misleading. It’s better suited for pool toys, towels, and summertime snacks. Other uses for such structures include art or music studios, recreation rooms, and workshops.
Is it better to build a traditional pool house or an ADU next to your pool?
Your decision will depend on your goals. Building a full ADU with a kitchen and bath significantly increases your home’s resale value. An ADU offers flexible living arrangements and the potential for rental income. In contrast, a pool house is often cheaper to build since it requires less finished space. Pool houses also face different setback and building requirements compared to ADUs.
For example, in San Diego County, the total area of detached non-habitable accessory buildings cannot exceed 25% of your main residence’s living area or specific lot-size limits. For lots under half an acre, you can build up to 1,450 sqft of accessory buildings; for one acre, it’s 2,000 sqft; and for two acres, it’s 3,000 sqft, as specified in PDS-901. You can also build a 1,200 sqft ADU in addition to non-habitable structures. ADUs require a 4-foot setback from property lines, while pool houses have a more lenient requirement of 3 feet.
Thinking about who will build it?
Before you hire a remodel or general contractor who says they can “handle everything,” check out our article: If Your Remodel Contractor Says They’ll Handle Your ADU, Pool, and Landscaping… Run. We explain why ADUs are not just another remodel, and how choosing a true ADU specialist can save you from delays, scope gaps, and costly surprises.
Can you build a pool house AND an ADU?
Yes, in most cases you can build a pool house in addition to a full ADU. However, this depends on the jurisdiction very similarly to restrictions on building guest quarters. The County of San Diego, for example, does allow pool houses in addition to ADUs.
What are the construction requirements for building a poolside ADU?
As you begin your poolside ADU build, keep a distance of at least 5′ between the unit and the pool. Both the pool and the ADU exert significant force on the surrounding area, so consider how they interact. For example, the ADU foundation applies pressure to the soil beneath it. If the pool is too close, its walls may unexpectedly support the foundation which are not what they were designed to do.
Water damage is the top maintenance issue for any structure, especially near a pool. First, ensure water does not penetrate the building envelope. Second, direct water away from the structure. You might need to slope the concrete slab away from the unit toward a drain to prevent pooling and foundation erosion. Discuss the layout with your contractor for effective design advice.
In Southern California, building is generally straightforward, with few weather concerns. However, water remains a significant challenge. Avoid flooding footings before pouring the foundation to keep the unit “dried in.” After the foundation, framing and other trades can get wet without issue. Your ADU will also need extra reinforcements if it’s built near a pool, depending on how close it is, which can be assessed during the feasibility phase of your project.
What are other requirements for a poolside ADU?
In order to get a building permit for an ADU when there is a pool on the premises, the homeowner must prove that the swimming pool barrier safety requirements are met. The County of San Diego includes a list of acceptable pool safety features. This includes items like enclosures, electrically operated pool covers, and swimming pool alarms.
What is the best floor plan for an ADU near a pool?
When considering the best floor plan for a pool house or poolside ADU, think of how the space will be used. Is there a path of travel to consider? For example, you may want to place a bathroom where it can be accessed from the outside, such as this 1BR/1BA ADU in Encinitas. Or perhaps you might place the kitchen in an area easily accessible from the exterior for entertaining. The last thing you want is to have people – who are soaking wet from the pool – walking through a living area to access more highly trafficked areas like kitchens and baths. On that note, also consider adding a second entrance to one bath from the outside of the structure for easier access.
For some inspiration, take a look at our completed and in progress pool house ADUs.
Can a pool house have a bathroom or a kitchen?
The short answer is yes, with several conditions. A municipality will look closely at building plans to determine if they are indeed designed for a non-habitable space. You can check the full list of thresholds for determining when non-habitable space qualifies as habitable space from San Diego County. However, here is a quick list of what could trigger review as an ADU:
- A closet and/or wet bar. A wet bar may be allowed as long as the structure is not designed so that it could easily result in an unpermitted ADU. For example, it can be on outside wall of pool house under a terrace.
- Floor plan indicates internal access to a storage room as the only access to the storage room
- Floor plan indicates more than one room. This excludes half baths, saunas, and a small changing/dressing rooms
So, if you are looking to add a full bath to your new pool house, for example, it is most advisable to build that bathroom with exterior access only if you wanted it permitted as a traditional pool house. This provides a clear distinction between a habitable and non-habitable space.
Can you convert a pool house into an ADU?
In some cases, yes. However, most pool houses are not built to ADU standards. Converting one usually requires:
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New foundation or structural upgrades
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Full plumbing and sewer connection
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Electrical upgrades
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Fire separation and insulation
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Full kitchen installation
In practice, many homeowners find it’s more cost-effective to build a purpose designed pool house ADU from scratch.
Filling in a Pool to Build an ADU
If you’re thinking about filling in your existing pool to make space for an ADU, there are several important factors to consider. Pool conversions offer a great way to reclaim valuable backyard space, especially if your pool is no longer in use or has become expensive to maintain. By replacing your pool with an ADU, you can reduce upkeep costs, eliminate safety concerns, and create a new income-generating unit or additional living space.
Cost of Filling in a Pool
Filling in a pool requires proper planning and professional contractors to ensure the space is stable enough to support a new structure like an ADU. Pool removal typically involves draining, demolition and removal of the pool shell, and filling the area with imported soil to create a stable base. You’ll also need compaction testing and over-excavation to meet construction standards.
The ballpark cost for pool fill-in, including site preparation & soils testing, can range from $25,000 to $35,000 depending on the size and complexity of the project. SnapADU can take on this site prep as part of our full project scope.
Permitting Requirements
As with any construction project, obtaining the necessary permits is crucial. Local jurisdictions may have specific regulations regarding pool removal and ADU construction, and it’s essential to ensure compliance. A feasibility study will help identify any zoning or permitting challenges, making the process smoother.
Site Preparation
After the pool is filled in, the area must be properly graded and compacted to create a stable foundation for your ADU. Site preparation includes ensuring proper drainage, which is especially important when converting a pool area. Our team handles this process as part of our site preparation services. We ensure your ADU is built on a solid, well-prepared foundation.
Ready to talk about your ADU? Request a free consult with our team.
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