Who permits a septic system in Lago Vista?
Not Travis County. For the City of Lago Vista the on-site sewage authority is the Lower Colorado River Authority. LCRA's own program materials put its jurisdiction two ways. One is a 2,000 foot zone around Lake Travis.
The other is the city limits of Lakeway, Jonestown, Briarcliff, Volente, Lago Vista and Granite Shoals. TCEQ's authorized agent list says the same thing. So the whole city answers to LCRA, not only the lots down on the water.
LCRA's rules require a permit before a septic system is built or installed. That holds regardless of the lot or tract size. The ten acre rule people read about sits in the state statute, and LCRA's own rule is written without it. Repairs and alterations need authorization too.
Travis County can still require its own development permit on top of the LCRA septic permit. The LCRA office issues the septic permit and the approval for continued use. We tell you which office your address answers to before you spend money, and we handle permit paperwork with you.
Selling a Lago Vista house on septic means an LCRA inspection
When a property on septic transfers to a new owner, LCRA has a written procedure for it. If the system was inspected within five years of its approval date, a walkover inspection is usually enough. If it has not been inspected in five years, the tank interior gets inspected too. Same if LCRA never approved the facility at all.
That second case is the one that catches sellers out. LCRA's rules say the tanks shall be uncovered and access to the tank interior provided by the owner. The inspector looks at water-tightness, the inlet and outlet devices, and sludge and scum build-up.
LCRA's sale checklist adds one more thing. Somebody has to be there to lift the port covers and put them back. If the tank needs pumping, a copy of the pump out manifest goes to LCRA. That manifest comes from a TCEQ-registered sludge transporter, which is what we are.
LCRA's checklist also says it does not inspect on Fridays. An application takes two full working days to process. That is why a real estate septic inspection and a pump-out belong at the front of an option period.
Thin soil, steep lots and why so many systems here are aerobic
The USDA soil survey rates most of Travis County very limited for a conventional septic drainfield. Roughly 87 percent of the rated acreage falls that way. On this side of the county the problem is rock rather than clay. Brackett, the largest mapped soil in Travis County, hits bedrock at about 15 inches.
Slope is the other half of it. Travis County has 15,853 acres rated limited for absorption fields because the slopes run over 30 percent. That limitation does not appear in the Williamson County table at all. Thin soil over rock is also where drainfields fail, and drain field repair covers that.
The permit record follows. LCRA authorized 124 new systems in its Travis County jurisdiction in 2025. Of those, 78 were drip and 18 were spray. Exactly one was a standard trench or bed.
So aerobic systems are ordinary here, and our part of one is the pumping. Every compartment gets emptied, and an aerobic install has more of them than a conventional tank. The maintenance visits, the chlorine and the reports filed with LCRA belong to a licensed maintenance provider. Putting in or replacing the unit itself takes an installer licensed for non-standard systems.
Lake houses that sit empty, and lids nobody has seen in years
A lot of Lago Vista houses are not lived in full time, and LCRA plans for that. Its sale checklist calls for a water load test when a house has sat unused for seven consecutive days. That test runs three days at 100 gallons per bedroom.
A tank fills on what goes into it, not on the calendar. A weekend house can run longer between pump-outs than a full-time house with the same tank. The holiday week is where that catches up with people.
A house serves two people most of the year. Then it hosts ten over Thanksgiving, and solids move toward the outlet in a hurry. TCEQ recommends pumping conventional systems every three to five years. Texas A&M AgriLife Extension publishes a table by tank size and number of people.
We measure the sludge and scum while the tank is open and show you where the levels sit. The lot lines here are old too. LCRA's rules exempt single family lots recorded before September 17, 1971 from its minimum lot sizes. Lots created between that date and January 1, 1988 had to hold half an acre.
Drainfields installed before September 17, 1971 are inspected through sight holes the owner provides. On systems that age the lids are often buried and unmarked. So locating a buried tank comes first. Then septic tank risers bring the lid up to grade for next time.
Communities and areas we serve around Lago Vista: Bar-K Ranches, Highland Lake Estates, Oaks at Highland Lake Estates, Lago Vista Country Club Estates, Tessera on Lake Travis, Point Venture, Volente, Bar K Ranch Road, Lohman Ford Road, Boggy Ford Road, RM 1431, Dawn Drive.
Lago Vista ZIP codes served: 78645.