Septic system requirements in Texas

What landplan.io applies when it designs a septic system in Texas: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.

Updated 16 October 2026

Design a septic system for an address in Texas

Reviewed landplan.io designs by Texas's own rules, which our staff reviewed against the state's regulations. Last published 16 October 2026.

7system types permitted

750 gallonssmallest septic tank

65septic companies located here

253 of 254counties with parcel data

Septic systems allowed in Texas

The system types landplan.io permits in Texas:

Absorptive Drainfields
ET Drainfields
Low Pressure-dosed Drainfields
Drip Irrigation
Mound
Surface application disposal
Soil Substitution System

Septic tank size in Texas

The daily design flow of a home: 75 gal/day per bedroom, at least 225 gal/day. The septic tank is sized from that flow:

Septic Tank: minimum size by daily design flow
Daily design flow	Minimum tank
up to 250 gal/day	750 gallons
250 to 350 gal/day	1,000 gallons
350 to 500 gal/day	1,250 gallons

Septic setbacks in Texas

Minimum distances
From	To	Distance
LineString	Private water line	10 Ft
LineString	Streams, Lakes, Creeks	50 Ft
Point	Public water wells	50 Ft
Point	Wells and underground cisterns	100 Ft
Polygon	Existing Septic Component to be Abandoned	5 ft
Polygon	Lakes, Pond, or Retention Basin	50 Ft
Polygon	Swimming Pools	5 Ft
Polygon	Underground Easements	1 Ft

Soil loading rates in Texas

The range over the soil groups of each table
Table	Lowest	Highest	Soil groups
Soil Loading Rate	0.1 gal/day/ft²	0.5 gal/day/ft²	5

landplan.io picks the rate from the soil test: texture, structure and percolation.

These are the values the landplan.io design engine applies in Texas. Confirm a design with the Texas health department or your county's before you build.

Septic system costs in Texas

Delivered prices (October 2026)
Product	Median	Typical range	Listings
Septic Tank	$1,232	$1,213 – $1,246	111

The Texas price index: every product type, month by month.

Parcel data in Texas

landplan.io has parcel boundaries for 253 of Texas's 254 counties: the counties where 100% of the state's people live. Type an address there and the design starts from the parcel.

Septic companies, designers and jobs in Texas

Where the rules come from

The regulations and documents landplan.io's Texas rules are read from:

Chapter 285 - On-Site Sewage Facilities (OSSF) (30 Tex. Admin. Code (TAC) Chapter 285)
Chapter 285 - On-Site Sewage Facilities, as adopted June 14, 2023 (TCEQ clean copy, with the full Table X, 285.91(10)) (30 TAC 285.91(10), Table X)
North Carolina State University Sea Grant College Publication UNC-SG-82-04 (285.33(d)(3))

Septic rules by county in Texas

Questions

What septic systems are allowed in Texas?

landplan.io permits these system types in Texas: Absorptive Drainfields, ET Drainfields, Low Pressure-dosed Drainfields, Drip Irrigation, Mound, Surface application disposal and Soil Substitution System.

What size septic tank do I need in Texas?

landplan.io sizes the septic tank in Texas from the daily design flow: up to 250 gal/day: 750 gallons; 250 to 350 gal/day: 1,000 gallons; 350 to 500 gal/day: 1,250 gallons. A home's design flow is 75 gal/day per bedroom, at least 225 gal/day.

How far must a septic system be from a well in Texas?

landplan.io keeps these distances in Texas: Point to wells and underground cisterns: 100 Ft; Point to public water wells: 50 Ft.

Does landplan.io have parcel data in Texas?

Yes, for 253 of Texas's 254 counties.