How to Find Your Septic Tank

Step 1: Pull the permit record (the 10-minute desk method)

Every permitted septic system in Texas has a site drawing on file with the permitting authority showing the tank and field location. For most local homes that is the Ellis County Department of Development; parcels on the Dallas, Tarrant, or Johnson county sides file with those counties instead. Call or email with your address and ask for the OSSF permit file. Older rural systems sometimes predate permitting, in which case move to Step 2.

Step 2: Follow the sewer line

• Find the exit point. In a crawl-space home, follow the 3–4 inch main drain pipe to where it leaves the foundation. On slab homes, look for the cleanout: a capped pipe sticking a few inches out of the ground near the house.
• Walk the line. Tanks are almost always set 10–25 feet from the house, in a straight line from the cleanout, on the downhill side if there is any slope.
• Read the yard. A rectangular patch where grass grows faster or greener, a shallow depression, or a spot that melts frost first often marks the tank.

Step 3: Probe carefully

Use a thin metal rod or soil probe, pushed gently every couple of feet along the suspected line. A tank answers back as a flat, hard surface about 4 inches to 4 feet down. Probe at a shallow angle and stop at resistance. Never probe hard: older tanks can have deteriorated lids, and plastic components, electrical lines to aerobic units, and shallow spray lines are easy to damage.

If you have an aerobic system, you are already done

Most Ellis County homes built since the early 2000s run aerobic systems, and those are designed to be found: two or three round lids at or just above grade, a control panel on the house or a post, and sprinkler heads in the yard. The lids sit directly on top of your tanks.

Where tanks are NOT allowed to be

Knowing the setback rules narrows the search fast. Tanks are not under the driveway or the house (with rare grandfathered exceptions), not within 5 feet of the foundation, not within 50 feet of a water well, and not inside a utility easement. Cross those zones off and the likely area shrinks to a strip or two of yard.

Still can’t find it?

We locate tanks as part of every pump-out and inspection, using the records, a probe, and when needed a flushable transmitter that pings the tank location from inside the line. Once it is open, ask about risers: they bring the lid to grade so you never have to dig for it again, and they pay for themselves in avoided locate-and-dig fees in about two pump-outs.

Frequently asked questions

Next: figure out what size tank you have, or set your pump-out reminder so the lid you just found gets used on schedule.