New Septic Installation in Washington County, Texas
Licensed, bonded septic system installation for Washington County — Burton, Chappell Hill, Independence, Washington, Greenvine, Gay Hill and the surrounding rural communities.
Licensed & Bonded
Texas OSF installer
Permitted & Inspected
County health-dept approved
New Installs Only
Built right the first time
Free Estimates
No-obligation, on-site
Your Washington County septic installer
Across Washington County's rural land, most homes run on their own on-site septic system instead of city sewer. We design, permit, and install new septic systems for new construction, manufactured, and mobile homes throughout the county — including Burton, Chappell Hill, Independence, Washington, Greenvine, Gay Hill — handling the soil and percolation testing and the county OSSF permitting from start to finish.
We install new septic systems all across Washington County, from the rural edges of Brenham out to Burton, Chappell Hill, Independence, Washington-on-the-Brazos, Greenvine, and Gay Hill. This is acreage country between Houston and the Brazos bottoms, and outside Brenham's city limits most homesites have no sewer line to tie into — a new house or manufactured home out here runs on its own on-site septic system. We size it, permit it through the county, and install it to pass inspection.
What we install in Washington County
Site Evaluation & Perc Testing
We evaluate your soil and run the percolation test that determines how well your ground absorbs water — the foundation of a system that works.
System Design & Sizing
We size the tank and drainfield to your home's bedroom count and your soil's absorption rate, then engineer a layout that fits your lot.
Permitting & County Approval
We prepare and submit your on-site sewage facility (OSF) permit application and coordinate approvals with your county health department.
Excavation & Site Prep
We prepare the site and excavate for the tank and drainfield with the right grade and setbacks — protecting your wells, structures, and property lines.
Tank Installation
We set the septic tank, connect the inlet and outlet plumbing at the correct grade, and install the effluent filter and risers for easy future access.
Drainfield Installation
We install the drainfield (leach field) that disperses treated effluent safely into the soil, sized to your percolation results and available area.
We handle Washington County permitting
On-site sewage facilities (OSSF) are permitted at the county level. We prepare the application, submit the soil and design documentation, and see it through approval and final inspection — so your Washington County system is fully permitted and passes the county inspection.
In Washington County, your septic permit goes through Washington County Environmental Health, a division of the county's Engineering and Development Services, which administers OSSF permitting for the whole county. Every new, altered, repaired, or enlarged system needs a permit before work begins, regardless of acreage, and applications go through the county's online MGO Connect portal. A licensed site evaluator or professional engineer completes the required soil and site evaluation, the county issues a written Authorization to Construct before anything is dug, and a county inspector has to pass the system before it's covered. Aerobic systems also need a recorded Affidavit to the Public and ongoing maintenance by a county-registered provider. We handle that whole sequence for you, from the portal submittal to the final Notice of Approval.
Local OSSF permitting authority: Washington County Environmental Health (Engineering & Development Services)
Typical county permit fee: About $325 (county fees change — we confirm the current amount during permitting)
New to septic? Our guides cover the basics: How Much Does a New Septic System Cost in Texas? (2026) · What Size Septic Tank Do I Need? · What Is a Perc Test (and Why Does It Matter)?
Soil & site conditions in Washington County
Washington County is classic Brazos Valley blackland: much of the county runs to calcareous black clays like the Frelsburg, Bleiblerville, and Latium series, which drain very slowly and swell when wet. Those tight clays usually land in the least-permeable TCEQ soil classes, where a conventional gravity drainfield won't pass, so most new installs here are aerobic systems with spray or drip dispersal. The loamier Brenham-type soils and the sandier post-oak ground toward the north of the county can grade out better, which is why the on-site soil evaluation is what settles the design for your specific lot.
Cities & towns we serve in Washington County
We also install new septic systems across the rest of our service area: Harris County · Montgomery County · Fort Bend County · Waller County · Liberty County · Grimes County · San Jacinto County · Walker County · Colorado County · Austin County · Wharton County.
Washington County septic questions
Do I need a permit for a septic system in Washington County?
Yes. A new on-site sewage facility (OSSF) requires a county permit plus a soil/site evaluation before installation. We handle the full permitting process for you, start to finish.
How much does a septic system cost in Washington County?
It depends on your soil type, system type, and drainfield size. Use our instant estimator for a ballpark, then we confirm the exact price after a free on-site evaluation.
Do you install septic systems for manufactured and mobile homes?
Yes — manufactured and mobile homes on rural Washington County land are what we install most. We size and permit the right system for your home and lot.
Who issues septic permits in Washington County, and what does the permit cost?
Washington County Environmental Health, a division of the county's Engineering and Development Services at 3650 Highway 36 North in Brenham, administers OSSF permitting countywide. The single-family residential OSSF permit fee is $325 on the county's current fee schedule. Fees change over time, so we confirm the exact amount when we file — the office can be reached at (979) 277-6290.
What are the steps to get a septic system permitted in Washington County?
A licensed site evaluator or professional engineer completes the soil and site evaluation, the system is designed to TCEQ 30 TAC Chapter 285, and the application goes through the county's online MGO Connect portal. The county issues a written Authorization to Construct before any work starts, a county inspector must pass the system before it's covered, and the county issues the Notice of Approval after. We manage the whole sequence as your installer.
Do I need a permit even on a large rural tract?
Yes. Washington County requires an OSSF permit for every new, altered, repaired, or enlarged septic system regardless of acreage — routine tank pumping is about the only thing exempt. If a seller or neighbor tells you a big tract skips the permit, that's not how this county runs it.
Is there a minimum lot size for a septic system in Washington County?
For lots subdivided on or after June 15, 2009, the county requires at least 1.5 acres if the home is on a private well, or 1.0 acre if it's on public water. Smaller or older lots aren't automatically ruled out, but they typically need a professionally designed system. We check where your parcel falls during the site evaluation.
Why do so many Washington County homes need an aerobic system?
The county's blackland clays — series like Frelsburg and Bleiblerville — drain very slowly and usually grade into the least-permeable TCEQ soil classes, which rules out a conventional gravity drainfield on many sites. An aerobic treatment unit with spray or drip dispersal is the design that passes. The sandier post-oak ground in the north of the county can be the exception, and the on-site soil evaluation is what decides.
Can you install a septic system for a manufactured or mobile home near Brenham?
Yes. Manufactured and mobile homes on acreage around Brenham, Burton, Chappell Hill, and the rest of the county need their own permitted septic system just like a site-built house. The same county process applies — soil evaluation, MGO Connect submittal, Authorization to Construct, and inspection before cover — and we handle all of it.
Get your free Washington County estimate
Tell us about your property and we'll size your system and schedule a free, no-obligation on-site evaluation.
Buying land in Washington County? Check the soil before you close
Enter any address and get the USDA soil rating, FEMA flood zone, mapped wetlands, and the septic system type you're likely looking at — free, in about ten seconds.
Serving property owners across the region
Counties We Serve
- Harris County
- Montgomery County
- Fort Bend County
- Waller County
- Liberty County
- Washington County
- Grimes County
- San Jacinto County
- Walker County
- Colorado County
- Austin County
- Wharton County
Don't see your county?
We're often able to serve nearby areas too. Reach out with your property's location and we'll let you know if we can help.
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