Plumbing in Harris County
Harris County is one of the most populous counties in the country, and a large share of its residents live outside any city limits. In those unincorporated areas, water and sewer service usually comes from a municipal utility district (MUD) or similar district rather than a city, and Harris County, not a city, handles development and floodplain permitting. That changes who you call for a water outage, whose rules apply to a new sewer connection, and which office reviews work in a flood zone.
The county’s flat terrain, heavy rain and history of major floods, including Hurricane Harvey in 2017, make floodplain rules and backflow and backwater protection practical concerns. Homes beyond district sewer service rely on on-site sewage facilities (septic systems), which are permitted at the county level. Gulf Coast clay soils move with moisture, so slab leaks and under-slab drain problems are common across the county.
County seat: Houston
What Harris County oversees that affects your plumbing
Unincorporated-area permits
Outside city limits, Harris County handles development permits, including floodplain review, for work that changes structures in flood-prone areas.
MUD water and sewer
Many unincorporated neighborhoods get water and sewer from a municipal utility district. The MUD, not the county or a city, maintains the public mains and sets connection rules.
Septic systems (OSSF)
Homes outside sewer service use on-site sewage facilities. New systems, repairs and many modifications need county permitting and must follow state rules.
Floodplain management
The county administers floodplain regulations in unincorporated areas, which affects elevating equipment and rebuilding after flood damage.
City plumbing guides in Harris County
Communities in Harris County
Spring · Katy (unincorporated) · Cypress · Humble · Atascocita · Channelview · Crosby · Klein
Harris County plumbing questions
Who supplies my water if I live in unincorporated Harris County?
Usually a municipal utility district or water supply corporation. Your water bill names the provider; that district handles main breaks, outages and connection rules.
Do I need a county permit for plumbing work in unincorporated Harris County?
Work in a floodplain and septic system work commonly involve county permitting. Check with Harris County’s permitting office before major work, especially after flood damage.
How do I find out if my Harris County home is on septic?
If your bill shows no sewer charge from a district or city, or your property records show an on-site system, you’re likely on septic. The county keeps records of permitted systems.
Should I install a backwater valve in Harris County?
In areas where heavy rain overwhelms sewers, a backwater valve helps prevent sewage from backing into the home. Check your district’s requirements before installing.
Why are slab leaks so common in Harris County?
Gulf Coast clay swells and shrinks with moisture, moving slabs and stressing the supply lines and drains beneath them.
