What is a backyard cottage?
It is a detached accessory dwelling: a complete, separate home on the same lot as your house. Houston's code calls this a second dwelling unit. Owners use them for parents, adult children, a home office or a long-term tenant.
How large can a backyard cottage be in Houston?
As of October 2026, inside city limits, a second unit of up to 1,500 sq ft lets the lot keep its single-family residential status under Chapter 42. City planning materials tie parking to unit size: a unit of 1,000 sq ft or less may need no added space when certain criteria are met, and a larger one generally needs one space. We confirm the parking count for your lot during design.
Your deed restrictions can set a smaller limit, or ban a second residence outright. The city states that its 2023 changes do not override active deed restrictions.
What does a Houston yard demand of the foundation?
Two things decide most foundation budgets here. First, the flood map: as of October 2026, Houston's Chapter 19 rules require new buildings in the 500-year floodplain to sit two feet above the 500-year flood elevation. Second, the soil, which a geotechnical report or the engineer's design accounts for. Both are why we price the slab only after a site visit.
What utility work is involved?
- A sewer connection from the cottage to the house line or the city main, with enough fall over the distance.
- Water service, sized for a second kitchen and bathroom.
- An electrical load check; a new service or a subpanel is common.
- Separate air conditioning, usually a heat pump or ductless system sized for Houston summers.
When is a cottage the wrong choice?
It depends on the lot. On a narrow lot with a long sewer run, or a yard deep in the floodplain, a garage apartment can put the same living space higher and closer to the utilities. We show you both options when both are legal.
How much does a backyard cottage cost in Houston?
As of October 2026, one 2026 Houston market guide estimates about $140,000 to $220,000 all-in for a new 600 sq ft detached unit. Elevation, the sewer run and finishes push projects outside that range. See the Houston ADU cost guide.
Related
Rules as of October 2026, from City of Houston Planning & Development (Livable Places, effective November 27, 2023) and Houston's Chapter 19 floodplain ordinance as amended in 2018.
Check what your lot allows
Send your address. We read the restrictions and the flood map before you pay for a single drawing.