On July 10, Austin Water sent the plant's neighbors a short notice. The lime-delivery contractor would run its blower on July 13 and 14, from 8 a.m. to 5 p.m., and neighbors might hear "a slight temporary noise increase." The lime blower is one of the two loudest sources Austin Water's own consultant measured at the Ullrich Water Treatment Plant, and the July notice didn't say whether a silencer had been fitted. In November 2025, the utility told neighbors a blower silencer would be installed in 2026.
The utility's next neighbor meeting is Monday, Oct. 19, at 5:30 p.m. at West Lake Hills City Hall. West Lake Hills says it will cover current projects and "continuing work on sound mitigation strategies." The timing makes this meeting more important than a routine update. On the city's capital projects explorer, the plant's largest upcoming job shows a construction start of fall 2026. Every published schedule for the larger noise fixes is still at the feasibility stage.
What the plant is, in a few numbers
Ullrich is the largest of Austin Water's three treatment plants. It is rated to treat 167 million gallons a day, uses a lime softening process, and pulls raw water from Lake Austin. Austin Water's slides give 1968 as the year it was built and 2006 as the year it grew from 100 to 167 million gallons a day. The slides also say the plant serves customers mostly in South Austin, including West Lake Hills.
Lime softening matters to the people next door. The process leaves calcium carbonate in the basins, so each basin has to be cleaned out about once every two years. Lime also arrives by truck and is blown into the plant. Two of the loudest things the plant does are built into how it treats water.
Where the sound comes from
The complaints have a public record. In January 2020, the Austin American-Statesman reported neighbors' complaints about heavy trucks at night, humming during the day, vibration and plant lighting. The plant's operator told the paper that Ullrich runs around the clock and that sludge trucks sometimes load and weigh on site.
Austin Water then hired Kennedy Jenks to measure the sound. The firm recorded ambient sound and vibration from Nov. 17 to 21, 2022, including nighttime levels and specific tasks like basin cleaning. The measurements focused on Rocky River Road, Rocky River Cove and Rocky Creek Drive.
The firm's December 2023 modeling report listed the sources neighbors can hear: lime-delivery blowers, water falling out of the basins, HVAC, truck traffic, general operations and periodic basin cleaning. Basin cleaning and the lime blowers produced the highest readings in the study.
| Source named in the 2023 study | How often it happens | What has been done or proposed |
|---|---|---|
| Lime-delivery blowers | With each lime delivery | Using the indoor blower cut sound by more than 11 dBA compared with the truck-mounted one. A silencer on the indoor blower is modeled to cut about 6 dBA more. |
| Basin cleaning | Each basin about every two years | Work limited to 8 a.m. to 5 p.m., no weekends or holidays |
| Trucks, deliveries, hauling | Ongoing | Limited to daytime hours since 2020 |
| Basin waterfalls, HVAC, operations | Continuous | Barriers on the basins and along the driveway and fence were modeled. Feasibility is still under study. |
The fixes so far are mostly about scheduling
So far, nearly every change has been about when and how equipment runs. Very little new hardware has been built. In 2020, the Statesman reported that Austin Water had slowed its exhaust fans, muffled the travel alarms at the front gate, moved truck deliveries, hauling and trash pickup to daytime, and scheduled noisy maintenance to finish before evening. In early 2021, high-pressure washers used for basin cleaning bothered nearby neighbors. Plant staff responded by building a plywood-and-scaffolding barrier about 10 by 40 feet around the equipment, the City of West Lake Hills reported. By November 2023, basin cleaning had a fixed window of weekdays from 8 a.m. to 5 p.m.
The most recent physical fix came in December 2025. Temporary electric pumps for the Process Drain and Support project were turned on, and Austin Water said it had installed sound panels around them.
Barriers on the basins, at the driveway and along the fence line remain on paper. Kennedy Jenks's model treated them as options. The report itself said feasibility, effects on operations and maintenance, materials, construction limits, cost and schedule all still needed study. Austin Water hired the same firm again in August 2025 to look at exactly those questions. Its November 2025 slides set two goals: install the blower silencer in 2026 and decide which other options are feasible by 2026. A year earlier, the October 2024 presentation had estimated 2027 for sound-mitigation construction.
None of the Austin Water updates sent to neighbors in 2026 say the silencer has been installed.
The job Austin Water itself says will be louder
The next major project is the Inherently Safer Disinfection Conversion. It replaces chlorine gas with sodium hypochlorite generated on site and replaces anhydrous ammonia gas with liquid ammonium sulfate. It also includes a new pipeline. In its November 2025 slides, Austin Water listed one expected effect for neighbors:
"Increased Construction Noise"
The two official sources disagree on when it starts. The November 2025 slides say construction begins in 2027 or 2028 and lasts about four years. The city's capital projects page for project 5335.008 lists an anticipated start of fall 2026, an anticipated finish in summer 2029, and $70.9 million in planned spending, with $7.1 million obligated so far. The schedule has already moved once. The October 2024 presentation had construction starting in fall 2025.
The project with a published noise warning has a start date between this fall and 2028. The larger mitigation structures had an estimated construction year of 2027 as of 2024, and the most recent public word on them is a decision expected sometime in 2026. Depending on which date holds, neighbors could spend years of disinfection construction with no barriers built yet.
Everything else on the site right now
Several smaller jobs overlap with that window:
- Process Drain and Support Systems Improvements. The work includes an automated sludge crossover vault, a rebuilt instrument air loop, a larger clarifier flushing system and hot-water washing for the centrifuges. The November 2025 slides priced it at $15 million. The city's project page shows $21 million in planned spending and an anticipated finish of summer 2026. That date has passed, and the page doesn't confirm the project is complete.
- Low Service Pump Station Electrical Feed Renewal. This $35 million project replaces the substation built in 1969 that powers the pumps drawing water from Lake Austin. It adds a new substation building, a duct bank, an access road and stormwater-quality work. Austin Water's project page says construction is underway and should finish in 2026.
- Locker room, door and window renewal. Austin Water's page calls it a roofing, door and window renewal. The city's explorer lists $4.4 million planned and construction anticipated from fall 2026 to summer 2027.
- Lime Feed Loop and Polymer Feed System. Both appear on Austin Water's list of current projects. Neither public page loaded with a schedule or budget.
Austin Water says all of this work stays inside the plant's existing footprint and doesn't increase its rated capacity. Work around the grounds counts too. In July 2025, Austin Water cleared brush and landscaped city property near Rocky River Road. It also planned to remove debris and dead wood along Redbud Trail to reduce wildfire risk, though no dates had been set.
Questions with answers that aren't public yet
The Oct. 19 meeting was moved from Sept. 21. These questions don't have public answers yet:
- Was the lime blower silencer installed in 2026, and was it running during the July 13 and 14 delivery?
- What did Kennedy Jenks's feasibility review decide about the basin, driveway and fence barriers, and is any of them funded?
- Which start date is current for the disinfection conversion: fall 2026 or 2027–2028?
- Will any mitigation be in place before that construction begins?
- Is the Process Drain project finished, and have the temporary pumps and their sound panels been removed?
- When are the next basin cleanings scheduled? Basins 7 and 8, which sit closest to Redbud Trail, were due to be cleaned before the end of 2025.
To report noise or another problem in the meantime, call 512-972-1000, choose option 1, and say you want to report a "Neighbor Concern" at the Ullrich Water Treatment Plant. Mary Anne Connolly in the Austin Water Public Information Office is the listed outreach contact at 512-972-2180. Earlier meeting slides and the 2023 sound study are posted on Austin Water's Ullrich project page, which also has a sign-up for project emails.
Deep Parikh follows long-running projects like this one for clients who own near them, because construction schedules and noise fixes end up on the same calendar as renovation and sale plans. If you'd like to talk through what the Ullrich timeline could mean for your own plans on Redbud Trail or Rocky River Road, Let's Connect.
