A lake water filtration system is what turns raw surface water into water you can drink, shower in, and run through appliances. It is built for lake houses that pump straight out of Lake Travis or Lake LBJ, and for Hill Country homes that collect rainwater. Lake owners usually call us in midsummer, when the water is cloudy in a glass, there is an algae taste in the water that carries through the coffee maker, and the raw water intake screen has picked up zebra mussel shells. Rainwater owners often call after the first big storm following a dry spell tints the cistern brown. Both are normal for surface water, and both are very manageable. A home on its own intake or cistern is running a small private water plant, and that job is bigger than a single cartridge filter on the dock pump. A well-built lake water filtration system is a chain of stages, each one sized from a test of your own water. Absolute Water Solutions is a TCEQ-licensed water treatment specialist (license WT001370), based in Spicewood since 2003, and every lake water treatment system for home use we design starts with the water itself, not a catalog.
Why lake water is different from well or city water
A well pulls from rock that filtered the water for decades. A utility runs coagulation, settling, membranes and chloramine before the tap. Raw Lake Travis or Lake LBJ water has had none of that. It carries turbidity that normally sits around 1 to 3 NTU and climbed past 400 NTU during the October 2018 Llano River flood; roughly 4 mg/L of dissolved organic carbon that feeds algae and exhausts carbon filters; bacteria and protozoan cysts such as Giardia and Cryptosporidium; and about 160 to 180 mg/L of limestone hardness, close to 10 grains per gallon, so scale still forms in the water heater.
Since 2017 it has also carried zebra mussel larvae. The mussels colonized Lake Travis and Lake Austin that year, Texas Parks and Wildlife lists Lake LBJ as fully infested, and by 2018 Lakeway MUD was pulling thousands of shells off its own intake. When a mass of them dies off inside a raw-water line, the water picks up an odor; that is what Austin Water customers reported in February 2019, with 2,451 complaints of pond-smelling tap water within days. On a private intake, a screen and a backwashing filter keep that from reaching the house.
The LCRA contract and your intake
Any lakeside owner pumping raw water from Lake Travis, Lake Austin or the rest of the Highland Lakes chain needs a Lower Colorado River Authority domestic-use contract on file: a 10-year term, up to 10 acre-feet a year, currently $165 per acre-foot with a 0.75 acre-foot minimum of about $124 a year, and an LCRA sticker on the pump. LCRA has run enforcement sweeps for unpermitted "straws" before. The contract is yours to hold; we design around it. The intake screen, the pump set and the treatment enclosure all have to survive a lake that dropped to 631.5 feet in February 2024, refilled after the July 4, 2025 floods, and sat at 676.8 feet, about 93 percent full, in September 2026. A swing of roughly 45 feet means a shallow intake can end up above the waterline in drought and a pump set can end up underwater when the lake refills, so we place both with that range in mind. If the house also has utility or well water, the two supplies need backflow protection so raw lake water can never cross into the treated side.
A treatment train built for Lake Travis water
There is no single filter for surface water. The stages go in a fixed order because each one protects the next:
- Screened raw water intake set below the low-water line, sized to pass full flow while excluding mussels, hydrilla and debris. This is the part you will be cleaning on a schedule during spring spawning season.
- Backwashing sediment filter, a multimedia or settling stage that takes out the mud and larval load and flushes itself, so a flood does not plug a cartridge in a day.
- Fine filtration down to 1 micron absolute, the stage that actually stops Giardia and Cryptosporidium cysts, which chlorine alone handles poorly.
- Carbon sized for the organic load, for the geosmin and MIB compounds that make summer water taste like a pond and to strip organics ahead of disinfection.
- Disinfection: a Viqua UV system where the water is clear enough for the lamp to work, or chlorination with a retention tank where it is not. How UV kills bacteria, and when it is the wrong choice, lives on our water purification page.
- Reverse osmosis at the kitchen tap for drinking and cooking water, polishing whatever the whole-house train leaves behind; see reverse osmosis drinking water systems.
Because the raw water is still hard, many lake homes add a softener after filtration; the test tells us whether yours should. All of it goes in an insulated enclosure, because the February 2021 freeze burst pipes all around the lake, and the dock pump and shoreline line are the parts of a lake system most exposed to cold.
Rainwater collection filtration
Rainwater is the other surface water we treat, and it is a different problem. Blanco County's plat rules recommend rainwater alongside wells, homes in Johnson City's Legacy Hills list 32,000-gallon systems, and Hays County owners are adding cisterns as Trinity wells drop. Off the roof, rainwater is soft and slightly acidic, so it does not need a softener but it does need a neutralizing stage to keep it gentle on copper plumbing. The rainwater collection filtration we build starts before the tank: a first-flush diverter dumps the first gallons that wash bird droppings and dust off the roof. Then sediment, carbon, UV and, usually, RO at the tap. UV is a standard stage on a cistern, not an option, because the first rain after a dry spell flushes turbidity and bacteria into the tank all at once.
Seasons: floods, turnover, drought
Surface water changes with the calendar. Spring rain and zebra mussel spawning load the intake screen. Summer heat stratifies the lake and drives blooms, which is when the algae taste in the water peaks; Lake Austin and Lady Bird Lake had blue-green algae events in 2019, 2022 and 2023. Fall is the Highland Lakes' flood season and lake turnover, when bottom water and its odor compounds come up. The October 2018 flood silted Horseshoe Bay's intakes and discolored the town's water for days, and the July 2026 Llano River flooding raised organics in Lake LBJ ahead of the city's annual free-chlorine conversion. Drought concentrates everything and exposes intakes. A properly built system rides through all of it with filter changes, a UV lamp swap about once a year, and a water test whenever the water changes on you.
Lakes we work on
From Spicewood we cover the south shore of Lake Travis, including Briarcliff and Highland Lake Estates, the north shore around Lago Vista, and Lake LBJ at Horseshoe Bay, where the whole town runs on lake water and the granite hills mean every trench hits rock. Pedernales River frontage and rainwater homes toward Round Mountain and Johnson City are the same service. If your water comes from a well instead, that is a different chemistry and a different page: well water treatment.
Start with the water, not the catalog. Call (512) 587-8188 or request a free estimate; we test the raw water first and size every stage to what it shows.