Can You Add an ADU in Rivercrest?

Thinking about adding an accessory dwelling unit on a Rivercrest property? You are not alone. An ADU can unlock guest space, multi‑generational living, or rental income. The catch in Rivercrest is that rules around Lake Austin shoreline, zoning, and utilities often decide what is possible. This guide shows you what to check, where to verify it, and how to move forward with confidence. Let’s dive in.

Quick answer for Rivercrest

In many cases you can add an ADU, but it depends on your exact parcel. Zoning, overlays, shoreline setbacks, impervious‑cover limits, sewer or septic status, and any deed restrictions all matter. Many Rivercrest lots fall under Lake Austin (LA) zoning. LA rules are more restrictive than standard single‑family zones and often limit or block a new unit without a variance. Start by confirming your property’s details with the City’s official guidance on Additional Dwelling Units.

What determines ADU eligibility in Austin

Zoning and lot size

ADU eligibility varies by the base zoning district. Historically, ADUs have been allowed in several single‑family zones when other conditions are met. Austin’s housing code updates (HOME Phase 1 and Phase 2) changed how some lot size rules work for one‑unit and two‑ or three‑unit configurations. The details differ by parcel and context. Review the City’s ADU page and the HOME materials, and then verify how rules apply to your lot with staff. The Planning Commission’s backup for HOME Phase 2 explains where lot‑size changes apply and where two‑ and three‑unit rules remain closer to 5,750 square feet; see the HOME Phase 2 backup.

Size, height, and FAR caps

City guidance and decisions often reference practical ADU caps such as a maximum of 1,100 square feet or 0.15 floor‑area ratio for a separate second unit, with a 550 square foot limit on upper‑story area in many cases. Height is typically under 30 feet. These numbers are enforced through the Land Development Code and case decisions. Always confirm the current numeric limits that apply to your zoning before you design. For examples, review Board of Adjustment materials from relevant cases, such as the March 14, 2022 docket.

Setbacks and separation

ADUs must meet site setbacks, building separation from the main house, and all technical codes. If your lot lies within a special district or overlay, extra requirements may apply. The City’s ADU guide summarizes eligibility and steps. Start your research on the City ADU page.

Parking and short‑term rentals

Minimum parking rules have been reduced in many Austin contexts, which helps smaller infill and ADU projects. Short‑term rental rules are a different story. The City adopted STR code amendments in 2025 that change licensing and density controls. If you plan to rent nightly, confirm current eligibility on the official Short‑Term Rental page before you invest.

Rivercrest constraints to check first

Lake Austin zoning and shoreline

Many Rivercrest properties are LA‑zoned or subject to Lake Austin rules. LA zoning imposes strict shoreline setbacks, commonly 75 feet from the lake, and tight impervious‑cover limits that vary by slope. These controls often reduce the buildable area even on large lots and can block new habitable space without a variance. To see how the City applies these rules, review LA‑related variance cases in recent Board of Adjustment packets, such as Sept 9, 2024 and Oct 11, 2021.

Sewer or septic status

Some Rivercrest parcels use private septic systems. Adding a dwelling on a septic lot can trigger utility and health constraints or require upgrades. If public sewer is available but not connected, you may need to extend service with associated permits and fees. If a parcel is outside Austin city limits, Travis County is the permitting authority. Start with Travis County’s accessory building permit guidance and confirm jurisdiction.

Deed restrictions and private rules

Even if the City allows an ADU, private covenants can limit what you build or how you use it. Restrictions may address separate units, rentals, building types, or heights, and some areas require architectural review. Pull title documents and recorded plats early. Listing notes for individual Rivercrest properties often mention whether covenants exist, but always confirm via official records. See an example of how private notes vary on a Rivercrest listing, then verify through county records.

Historic or NCCD overlays

If a property is a historic landmark or within a Neighborhood Conservation Combining District, additional design review and special standards may apply. HOME Phase 2 commentary indicates some NCCDs may retain control in certain situations. Confirm overlays and any review steps with City staff. You can reference community notes like the Hyde Park NCCD update here, then verify City interpretation for your parcel.

Your step‑by‑step checklist

• Verify jurisdiction and zoning. Use the City’s Property Profile and the official ADU page to confirm city limits, base zoning (SF or LA), and any overlays or historic designations.
• Measure the basics. Confirm lot size, floodplain, steep slopes, heritage trees, existing impervious cover, and shoreline setback lines if applicable. LA slope and impervious bands are key in Rivercrest.
• Confirm utilities. Check whether you have city sewer or septic and what upgrades may be needed. If outside city limits, review Travis County rules and septic approvals using the County’s accessory building resource.
• Pull private restrictions. Review recorded plats and deed covenants. Private rules can limit ADUs or rental use even when zoning allows them.
• Talk with the City. Schedule a Residential Zoning Questions appointment through the City’s ADU resources to confirm whether your idea is permitted by right or needs variances or rezoning.
• Design to the code. Size, height, setbacks, separation, and impervious cover all matter. LA‑zoned sites often require a variance request to the Board of Adjustment. For context, scan prior BOA cases like the March 14, 2022 docket.
• Permits and inspections. Submit building permits and any utility applications. Expect plan review and inspections. If variances are needed, build that timeline into your plan.

Smart design tips for Rivercrest ADUs

• Place the unit to respect shoreline and trees. Map your setbacks and protected trees first, then fit the building and drive within the remaining envelope.
• Keep the footprint efficient. On LA‑zoned lots, impervious cover is often the limiting factor. Smaller footprints and permeable hardscape can help.
• Right‑size the program. Design within common ADU caps, then refine after staff confirms the exact limits for your lot.
• Plan circulation and privacy. Thoughtful entries, lighting, and landscaping help the ADU live well and show well to buyers.
• Align with your use. If you plan a rental, confirm current STR licensing and density rules on the City’s STR page before final design.

Final thoughts

You can often add an ADU in Rivercrest, but the path is property‑specific. LA zoning, shoreline setbacks, impervious limits, and sewer or septic status are the usual swing factors. Start with official City resources, verify your parcel, then design within the limits or plan for variances where appropriate. If you want a local, concierge‑level guide as you weigh value, design, and resale, connect with Shavonne Martin to map a clear plan.

FAQs

Can I build an ADU on a large Rivercrest lot?

• Not automatically. LA zoning, shoreline setbacks, impervious‑cover limits, sewer or septic status, and private covenants can still block or shrink an ADU even on a big lot. See how LA constraints play out in Board of Adjustment packets like Sept 9, 2024.

What are the typical size limits for an Austin ADU?

• Many cases reference a maximum of 1,100 square feet or 0.15 FAR for a separate unit and a 550 square foot cap on upper‑story area, with height typically under 30 feet. Always confirm current limits with the City; see examples in the March 14, 2022 BOA docket.

Can I use a Rivercrest ADU as a short‑term rental?

• Maybe. Austin adopted STR code changes in 2025 that affect licensing and density. Review the City’s Short‑Term Rental page and confirm eligibility before you plan nightly rentals.

Do I need to live on site if I add an ADU?

• Owner‑occupancy rules have been shaped by local and state actions. Austin has not universally required owner‑occupancy for ADUs, but you should confirm current requirements with City staff or counsel based on recent laws and code updates.

Who permits my ADU in Rivercrest, the City or the County?

• If your lot is inside Austin city limits, you will work with City of Austin Development Services using the ADU page. If it is outside city limits, Travis County handles accessory structures and septic rules via their development services.