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Septic Setback Distances in Texas
Setbacks are why two identical houses on the same street get very different quotes.
A separation distance is ground the system may not occupy. Each one sounds reasonable on its own. The problem is that they overlap, and on a small or awkward lot what is left in the middle can be too little to hold a conventional drainfield at all. At that point the only thing that fits is a system that needs less ground, and a system that needs less ground costs more.
The distances
| From | Minimum |
|---|---|
| Private well | 50 / 100 ft |
| Public water well | 50 / 150 ft |
| Creek, pond, lake | 50 / 75 ft |
| Property line | 5 ft |
| Spray to prop. line | 20 ft |
| Swimming pool | 5 / 25 ft |
Where two numbers are given, the first is the tank and the second is the drainfield or absorption area. The 20 ft spray setback can drop to 10 ft where the sprinklers are run by a commercial timer, which is worth knowing on a narrow lot because it can be the difference between a system fitting and not.
Measured horizontally. Distances are taken across the ground, not through it, and they are measured from the nearest edge of the thing in question rather than from its centre.
These are minimums. A local authority may require more, a site condition may require more, and a designer may choose more. Nothing here entitles you to the smallest number in the table.
The ones that catch people out
Your neighbour's well counts
The distance is to the well, not to the property line, and a well twenty feet the other side of your fence takes its buffer out of your lot as surely as one of your own.
So does the creek that is only there sometimes
A defined channel with banks and a bed is a watercourse whether or not there is water in it the day of the site visit.
Spray systems have their own, larger set
A surface application system puts treated effluent into the air, so the distances it has to keep from lot lines, buildings and pools are bigger than the ones a buried trench keeps. If the plan is an aerobic system with spray heads, price the lot against the spray numbers rather than the trench numbers.
A licensed site evaluator has to answer that with a soil test; nobody can tell from a map. Send us your address and we will have local licensed pros quote the evaluation and the install. Request free quotes →