Four Crucial Questions About San Angelo’s Water

This article is part of The Concho Observer’s Water Monitor series, looking at water management in San Angelo and the Concho Valley. You can read our report on the city’s water quality report here. 

Even after the historic floods and rains of early July, Tom Green County and its neighbors have, once again, entered the first level of drought measurement: D-0 (Abnormally Dry). 

This measurement is marked by an increase in grass fires, with planting postponed, pasture growth stunted, hay cutting reduced, and producers starting supplemental feeding for livestock as surface water levels decline. 

San Angelo lies in Region F of the Texas Water Development Board planning system.

The Board is about to release their 2026 Water Plan, outlining extensive changes to our water sources over the next 30 years. 

These changes include direct and indirect reuse projects, where wastewater is treated to standards set by the TECQ, which provide controversy for headlines, but might be necessary to maintain the water supply going forward. 

Besides these long-term water problems faced by San Angelo, there are a great many shorter-term fixes that can help water quality in the next several years.

Namely replacing outdated infrastructure, like cast iron and asbestos concrete piping. 

Due to some natural facts of geology in San Angelo, problems are likely to continue for the foreseeable future, as the city presses on with the immense task of replacing its outdated infrastructure. 

Shane Kelton has worked for the City of San Angelo for 25 years, starting off in Parks, then moving to Operations, taking on the role of executive director of Public Works in 2021. He explained some of the larger problems that face the system:

What was the cause of the recent water discoloration issue? 

Two events in early September led to distinct inversion events: first a slug of dirty water, followed a week later by a new presence of Manganese, a basic element, in testing. 

First, Kelton says that the slug of “dirty water” from O.H. Ivie Reservoir entered the San Angelo treatment plant early in the morning of Aug. 30, around 3 a.m.

The water entering the plant at this time would have appeared to be very dark brown or black from the organic material and dirt. At night, of course, all water appears to be black, and so this went unnoticed until the turbidity meters started going off.

Turbidity is the way we measure the clarity of the water, measured in Nephelometric Turbidity Units (NTU), measured by how much light can pass through the water. For NTUs, the higher the number, the dirtier the water is. 

“Normally the water sits right at about 0.3 [NTU]” says Kelton.  “This water would look clear to the naked eye. While this slug of water was attenuating [settling, or decreasing in amount] the readings were around 7 [NTU].”

This type of event is known as an inversion event, where large scale temperature changes, for instance, lead to material settling-out into a separate layer.

Commonly, this can be seen in air pollution, where different temperatures cause hot and cold layers of atmosphere to stand apart from each other.

In water quality, inversions can lead to increased concentrations of minerals and elements. 

“It didn’t last long,” Kelton said, “It was really a quick spike, which is not normal for an inversion event. This cleared up quickly, within a day and a half, from the water coming out of Ivie.

“After that you have to flush the lines, and that’s what the crews were doing. Responding to customer complaints, and flushing water in those areas.” 

By Friday of that week, the first slug had been fully attenuated. 

Then the following week: “We then saw tinted water within our system again, but this didn’t come from Ivie, because the turbidity was normal. From here, further testing showed a spike in manganese.” 

However, as Kelton explained in last week’s city council meeting, they can treat the particulate, but they can’t treat the color. 

In trace amounts, manganese is non-toxic and is a naturally occurring element in soil and rock formations. In 2004, the EPA set the lifetime health advisory amount of manganese at 0.3 mg/l, or parts per million. 

Theres a few things you can do when the water turns turbid: first, you stop taking in water from the source of the contamination, in this case O.H. Ivie, and start moving to another source, in this case water from the Hickory Aquifer.

Then, while flushing out the service lines, the raw water testing is increased to two times per day, to track attenuation. 

As for that dirty slug of water, Kelton mentioned that it also consisted of “organics.”

When organics enter a system and are chemically purified, with chloramine or chlorine for example, the organics and the chemicals will create purification by-products, such as tri-halo-methanes. (THM) 

One violation noted in the city’s most recent water quality report was that THM levels exceeded the EPA maximum threshold of 80 parts per million.

Kelton explained that during this event the organic material was not of a substantive amount, and because they were able to switch back to the Hickory Aquifer water supply, the THM content was not a major issue at this time. 

What causes pipes to burst? 

Like thousands of cities around the country, San Angelo deals with the consequences of what were once considered ‘best practices’ in plumbing. Especially when it comes to the pipe materials. 

This leads to pressure issues, and this is one reason why — over time — the piping is replaced, and why in certain points of town, you might see a hydrant flushing for days or even weeks at a time. 

You might have seen hydrants running for extended periods this summer. Kelton explained the practice can be used to flush the system, to make sure that you don’t have buildups of pollutants, but the main purpose is to balance the water pressure around town. 

“In this area of town [by O.C Fisher Dam], we deal with pressure-plane issues,” Kelton said, “There’s a lot of old cast iron, and AC piping still in place.”

“We don’t want to cause any problems with the older plumbing inside these houses. Theres also a lot of PVC and galvanized pipe that were used, back before copper was so readily available.” 

Cast Iron is relatively cheap but corrodes easily, while AC piping, made from asbestos-concrete, is quite a bit stronger than other kinds of pipe, but releases asbestos when it does break.

Galvanized pipe, likewise, will corrode over time, and poly-vinyl-chloride, or PVC, while immune from these other problems can weaken over time. 

Additionally, the city balances the pH of the water to help prevent corrosion, since acidic conditions speed the corrosion of most pipes, while PH being too high will cause minerals begin building up inside the pipe. 

“In the last 20 or so years that I’ve been active with our system, there’s been a lot of infrastructure replaced,” Kelton said, “For a long period of time, the focus was replacing the 2-inch galvanized pipe with 6 and 8-inch PVC service lines. 

“We still have a lot of cast iron in the system. And, especially in parts of town with expansive soils and cast-iron pipes, you can have a lot of issues.”

Soil expansion occurs because of temperature and moisture shifts. In parts of town with clay-loam soils, the expansion and contractions with the weather changes quite dramatically. 

“Anytime there’s a disturbance in the soils, we start to see some of that sediment and color come back — even in pipes that are neighboring the burst pipe,” he said.

What does the future look like for the San Angelo water supply? 

The Texas Drought of 1950 to 1957 is referred to as the “drought of record.” Most conservation plans in recent memory are based on this, and the drought of 2010-2015. 

During the summer peak, San Angelo uses around 18 to 20 million gallons of water each day. In the winter, this drops down to 10 million. 

The most devastating drought in recent memory, which began in 2011, saw over 100 consecutive days in the triple digits, and less than 10-inches of rainfall. This was somewhat of a turning point in water usage for the city: 

“Those years, 2011-13, when we were so low, we had less than 12-months of water supply,” Kelton explained, “We were in the strictest use level in the drought contingency plans. That’s when we had to have some candid conversations with our community.  Since then, we saw usage drop off heavily.

“Before, there were 32-33 million gallons a day, sometimes 35.” 

Even as San Angelo’s population increases steadily, our water consumption has yet to return to pre-2011 levels. 

“The main priority is ensuring the water security for San Angelo, not just today, or next year, or five and ten years from now,” said Kelton, “When we look at the situation 30-40-50 years out, we must be preparing now for our water security.

“With the hickory coming online, through the indirect reuse project, and then with the Fort Stockton water, based off historic trends, that gets us out there to that 2060-2070 number. But that’s still us relying on surface water. 

What does ‘highly treated wastewater mean?’

The information in the next section is retrieved from the TCEQ permit: No. WQ0010641003

The original permit and all subsequent renewals and amendments can be found here.  

Indirect Potable Reuse is a process in which wastewater is recycled by being treated, and then released. Into the Concho River, in this case. It is then allowed to flow downstream, where it can be recaptured a few miles away, and piped back to the water treatment facility.

Before it can be blended into the river, there are guidelines that dictate the water being released back into the river must meet certain standards.

Standards which many parts of the river, if tested, might fail themselves. 

Step 1: From Our Homes to the Wastewater Plant

First, the water is captured by the wastewater treatment plant where it undergoes several steps:  

From the THEQ permit: “The City of San Angelo Wastewater Treatment Facility consists of an activated sludge process plant using the conventional mode.”  

According to the permit, the water follows through many different systems during treatment:

Two low-lift stations with bar screens and mixers, two additional bar screens, one grit collector, two fine screens, two parshall flumes (an open-channel flow-metering device), four primary clarifiers, two aeration basins, four final clarifiers, and one chlorine contact basin.

Each step before it reaches the final aeration and clarification has a separate odor control apparatus. 

The goal is to get the water as clean as possible; up to a standard which is laid out in the permit: specifically, that the water “does not reach more than 65 parts per million of any effluent in a single grab (or sample).”

Effluent is the engineering term for sewage.

One-part-per-million, which can also be expressed as one-milligram-per-liter, would be roughly equivalent to a single drop of iodine introduced into 10 gallons of water. 

Step Two: The Final Filtration

Then the water is released into the river where it flows down into the standard treatment facility. The water is then treated until it meets EPA guidelines.

Big Spring, Wichita Falls, and Abilene have used the practice of Direct Potable Reuse for almost a decade. The project here in Tom Green County would cost north of $200 million dollars. 

This project is currently being counted on, in region-wide calculations, to keep San Angelo and Tom Green County maintaining water supply for the next several decades.  

And so the difficult balance of keeping water to a desert town continues. As Kelton explains:

“With just the groundwater supply, that is not enough water for us to live off of when you start looking at that 2050-2070 timeframe.”