Waste Water and Spetic Systems

Weishuhn Engineering, Inc. has over 20 years of experience in wastewater design, permitting, installation and compliance pursuant to the Texas Pollution Discharge Elimination System rule (30 TAC 317) and the Onsite Sewage Facility Rule (30 TAC 285).

centralizing wastewater system commercial aerobic system open commercial aerobic system septic system using a leaching chamber


Domestic wastewater flows greater than 5,000 gallons per day and all industrial wastewater flows are subject to the Texas Pollution Discharge Elimination System (TPDES) rule. Domestic wastewater flows less than 5,000 gallons per day are subject to the Onsite Sewage Facility (OSSF) rule.

Domestic TPDES Experience

  • Westside Community Development Corporation; Engle, Texas
  • Pine Cove Corporation; Colorado County, Texas; and
  • Ellinger Sewer and Water Supply Corporation, Ellinger, Texas.

Industrial TPDES Experience

  • Postive Feed, Inc. Sealy, Texas; and
  • Bellville Tube/United State Steel, Bellville, Texas.


WEI focuses on designing, permitting and constructing OSSF facilities in Colorado, Fayette, Austin, Lavaca, Wharton and Waller counties, but has completed projects from central Texas to the Gulf Coast. Our projects range from residential projects rated for a few hundred gallons per day to commercial facilities rated for nearly the maximum limit of 5,000 gallons per day. Some of our larger projects include the following:

  • SPJST Environmental Nature Center, Fayette County, Texas;
  • Diversitech Corporation Manufacturing Facility, Domestic Wastewater flow, Columbus, Texas;
  • Town of Round Top commercial facility treatment system, Round Top, Texas;
  • Delta Tubular, Houston, Texas; and
  • K&B Machine, Houston, Texas.

We are qualified to design, permit and install conventional septic systems, low pressure dose, mounded low pressure dose, aerobic with drip or spray disposal and sand filter based system.

Commonly Asked Questions about OSSF Facilities

1. How do I get a standard, gravity flow, conventional wastewater system (also known as a septic tank and trench system)?
Must have household wastewater source at least 42-inch vertical profile of soils that do not exhibit signs of seasonal ground water and are not silty clay or clay; or spend a lot of money for an evapotranspirative bed system.

2. When do I need a low pressure dose system?
When silty clay or clay soils are present in the top 42-inch vertical profile and no signs of seasonal ground water are present.

3. Why do I need an aerobic with spray treatment system?
High strength wastewater from a restaurant or signs of seasonal ground water are present at depths less than 36-inch below ground sources.


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Sample Publications:
B-6098 On-Site Wastewater Treatment Systems: Alternative Collection Systems
L-5227 Onsite Wastewater Treatment Systems: Septic Tank/Soil Absorption Field
B-6171 Onsite Wastewater Treatment Systems: Homeowner's Guide to Evaluating Service Contracts