For a detached ADU in Cedar Park, most homeowners should budget $150,000 to $280,000 depending on size, finish level, and site conditions. A basic 500 to 600 square foot unit with standard finishes sits at the lower end. A 900 to 1,000 square foot two-bedroom unit with upgraded appliances, a deck, and central HVAC pushes toward the top. Those numbers include design, permitting, foundation, utility hookups, and construction. What they do not include is land, because you already own it. Get skeptical of quotes that leave out site work, permit fees, or utility connections. Those line items are real costs that add up fast in Central Texas.

Cedar Park has its own development code separate from Austin. Generally, detached ADUs are allowed on single-family lots, but setbacks, maximum square footage, lot coverage limits, and owner-occupancy requirements can all affect what you can actually build. The city has been updating its ADU ordinance in recent years, so the rules today may differ from what a neighbor built under two years ago. Before you commit to a floor plan or a budget, we pull your specific parcel's zoning and confirm what is currently allowed. That step is free when you work with us and it prevents expensive surprises later.

Honest answer: there are a few worth knowing before you start. First, the upfront cost is real. An ADU is not a weekend project, and financing one requires planning. Second, permitting in Cedar Park takes time, often two to four months depending on plan review workload, and that timeline is outside anyone's control. Third, if you plan to rent the unit, you become a landlord, which carries its own responsibilities. Fourth, a poorly designed ADU that does not fit your lot or your neighborhood can create drainage, parking, or privacy issues. None of these are reasons not to build one, but they are reasons to go in with a clear plan and realistic expectations.

The lowest-cost path is usually a garage conversion or an attached addition, because you are reusing an existing structure or sharing a wall and foundation with your main house. A detached garage converted to living space can come in at $80,000 to $140,000 depending on condition and finishes. If you are building from scratch, keeping the footprint under 600 square feet, choosing a simple rectangular shape, and avoiding a full second floor cuts cost meaningfully. Prefab or modular ADUs are another option some homeowners consider, but you still pay for site prep, utility connections, and Cedar Park permits, so the savings are often smaller than advertised. The cheapest ADU is still a significant investment.

At 1,000 square feet you have real flexibility. The most functional layouts we build in this range include a two-bedroom, one-bath plan with an open kitchen and living area, a one-bedroom plan with a dedicated home office and larger living space, and a two-bedroom, one and a half bath plan that works well for longer-term tenants or multigenerational family use. In Cedar Park's climate, covered outdoor space matters, so we usually build in a small covered porch or deck at that size. The right layout depends on who will use the space, whether that is a renter, an aging parent, or an adult child, and we design around that answer rather than a generic template.

From the first design meeting to a certificate of occupancy, plan on nine to fourteen months for a detached ADU. That breaks down roughly as one to two months for design and drawings, two to four months for city plan review and permitting, and four to six months for construction. Complexity, finish selections, and permit review times all affect where you land in that range. If you are hoping to have a unit ready to rent by a specific date, work backward from that target and start the process earlier than feels necessary. The biggest delays we see are homeowners who start the permit process six months after they meant to.

Most detached ADUs in Cedar Park require their own electrical service panel and can be served from your existing meter or set up with a separate meter depending on how you plan to use and bill the unit. Water and sewer typically tie into your existing service lines, though the city may require an upgraded meter or additional tap fees depending on your lot and the size of the ADU. These utility connection costs are real and often underestimated. We include a utility coordination review in our pre-construction process so you know what Cedar Park will require before we break ground.