Austin approves $89.7 million to end chlorine gas and ammonia use at the Ullrich water plant

The Austin City Council on Thursday approved a construction contract of up to $89.7 million to stop storing chlorine gas and anhydrous ammonia at the Ullrich Water Treatment Plant in West Austin. Hoodline reported the vote on Friday. For residents, the change affects both the safety of the neighborhood around the plant and the system that treats much of the city's drinking water.

What the council approved

The item, 26-2630, was number 21 on the Oct. 22 agenda. It awards the work to MGC Contractors for $81,555,085, plus an $8,155,509 contingency, for a total of up to $89,710,594. The money comes from Austin Water's capital budget, according to the agenda. The plant is in the 78746 ZIP code in District 8.

The staff recommendation for action explains the project:

• Ullrich opened in 1969 and supplies a large share of the city's drinking water.
• It now disinfects water with gaseous chlorine and anhydrous ammonia. Both have to be delivered in bulk, stored and handled on site.
• The project replaces them with salt-based sodium hypochlorite made on site by electrolysis, and with liquid ammonium sulfate. Staff call both "inherently safer" technologies.
• The plant must keep disinfecting water throughout construction. A temporary sodium hypochlorite system will run while the chlorine gas system is torn out.
• Staff said they do not expect major shutdowns that would affect customers, or any traffic impact, because the work is inside the plant.
• The contract allows 840 calendar days to finish.

The 10% contingency lets staff approve change orders up to that amount without returning to the council. Staff wrote that rejecting the contract would delay the end of chlorine gas and anhydrous ammonia use at the plant.

What our records add

One bidder. The city's solicitation opened April 27 and closed July 23, 2026. MGC Contractors "submitted the only responsive offer," the staff memo says. The contract meets the city's minority- and women-owned business goals with 10.54% MBE and 2.02% WBE participation.

No discussion at the dais. The contract was on the consent agenda. One person registered to speak on item 21 and passed when called. No council member pulled it, and the consent agenda was adopted without objection, with Council Member Natasha Harper-Madison absent.

Earlier review. The Water and Wastewater Commission recommended the contract on Oct. 14 on a 6-0 vote, with one commissioner off the dais, three absent and one seat vacant, according to the staff memo.

Earlier Ullrich votes. The council has approved other work at the plant without dissent. In July 2025 it voted 11-0 on consent to add $1 million to an engineering contract for Ullrich's centrifuge rehabilitation, bringing that contract to $3 million.

Other water items the same day. The council also approved a $10 million engineering contract for Austin Water's 2026 reservoir improvement program and $5 million in revenue bonds for the utility's waterline service replacement program, both on consent, per the agenda.

Who represents the area

The plant sits in District 8, represented by Council Member Paige Ellis, whose term ends in January. Voters will choose her successor on Nov. 3. We wrote about that race here.

What's next

With the contract approved, Austin Water and Capital Delivery Services can issue notice to proceed. The council will see more routine water-treatment purchases soon: the Nov. 5 draft agenda includes two contracts for calcium hypochlorite tablets and granules used for cleaning and disinfection in water treatment, worth up to $600,000 combined.