Harris County, TX
Plumbing and septic in unincorporated Harris County
Updated · Editorial team; not yet technically reviewed
Short answer
Outside city limits, Harris County's Office of the County Engineer permits septic systems (on-site sewage facilities, or OSSFs) through its ePermits portal. A permit needs a site evaluation by a professional engineer or registered site evaluator plus a system design, and the licensed installer must call for inspection at least 24 hours before the system is ready.
What Harris County handles
The Office of the County Engineer reviews plans and issues septic (OSSF) permits for unincorporated Harris County, submitted through ePermits. [1]
A residential OSSF application includes a site evaluation by a professional engineer or registered site evaluator, a septic design site plan, a technical report and a system flow diagram. [1]
An Authorization to Construct is issued after fees are paid, and the licensed installer must notify the permit office at least 24 hours before the system is ready for inspection. [1]
The County Engineer's water quality permitting group is reached at (713) 274-3900. [1]
City permit or county permit?
Inside Houston and the other incorporated cities, the city's building department handles plumbing permits and most homes are on city sewer. In unincorporated areas, many homes sit on septic or in utility districts, and the county handles the septic side. Check whether your address is inside a city before you apply for anything.
Septic trouble that looks like a plumbing clog
| What you notice | More likely |
|---|---|
| One fixture drains slowly | A clog in that drain line |
| Every drain slows, toilets gurgle, sewage smell outside | Full tank or failing drain field |
| Soggy, green patch over the field after dry weather | Drain field saturation or a break |
After a flood
Floodwater can saturate a drain field and push water back into the house. Use as little water as possible until the ground drains, and have the tank inspected before heavy use. If sewage backed up indoors, see sewer backup cleanup.
Further reading: How sewer camera inspections work.
City-specific guides in Harris County
- Water heater replacement in Houston
- Drains backing up in Houston
- High water bill in Houston: leak adjustments under city code
- Backflow testing in Houston
- Houston water service lines: the inventory and 'unknown material' letters
- Sewer line replacement in Houston: who can pull the permit
- Frozen pipes in Houston: why the city says don't drip
Common questions
Who issues septic permits in unincorporated Harris County?
The Office of the County Engineer, through its ePermits portal.
Do I need an engineer for a Harris County septic permit?
The site evaluation must come from a professional engineer or registered site evaluator, and the application needs a system design.
When can a Harris County septic system be built?
After fees are paid and the county issues an Authorization to Construct.
How much notice does Harris County need before a septic inspection?
The licensed installer must notify the permit office at least 24 hours ahead.
What phone number handles Harris County septic questions?
The water quality permitting group, (713) 274-3900.
Does Harris County permit plumbing inside Houston city limits?
No. Inside Houston the city's building department handles plumbing permits.
How can I tell a septic problem from a clogged drain?
One slow drain is usually a clog; every drain slowing with gurgling and an outdoor smell points to the septic system.
What should I do with a septic system after a Harris County flood?
Use as little water as possible until the field drains, and have the tank checked before normal use.
What if septic lines cross a property line in Harris County?
The application needs a joinder affidavit.
What forms go with a Harris County septic application besides the design?
The septic application, an Affidavit to the Public, an Acknowledgement of Testing Requirement form, and a property survey if the lot isn't in a recorded subdivision.
Cities and services in Harris County
- Plumbing services in HoustonHouston plumbing is shaped by its size and its mix of eras: close-in neighborhoods with older cast iron and clay lines, and large areas built out in t…
- Backflow Testing in TexasBackflow testing in Texas: the TCEQ tester license anyone testing or repairing assemblies must hold, test-at-install and annual rules, and gauge accuracy checks.
- Water Heater Replacement in TexasTexas law on water heater swaps: cities over 5,000 regulate water heaters and require permits beyond simple repairs, and the homestead exemption for owners.
- Plumbing in TexasStatewide code, licensing and climate for Texas.
Other Texas counties
- Septic systems in unincorporated Travis CountySeptic systems in unincorporated Travis County: the county OSSF permit, the soil evaluation and affidavits it needs, and maintenance contracts for aerobic systems.
- Septic (OSSF) permits in Tarrant CountyTarrant County permits septic systems in unincorporated areas and 23 contract cities. When a permit is needed, repair permits, and the ETJ around nearby cities.
- Septic systems and aerobic maintenance in Bexar CountyBexar County septic rules: every on-site system must be permitted, aerobic permits last two years, then owners keep a service contract with quarterly reports.
Sources (1)
- Harris County Office of the County Engineer, Residential OSSF/Septic permit · checked 2026-10-03