Water’s taste reflects its journey to the tap

A new place can sometimes be so unlike home that even something fundamental, like the taste of tap water, seems different. But it’s not just perception; water really does taste different in different places. Though the flavor differences can be jarring at first, it doesn’t necessarily mean there is anything to be concerned about.

Water’s flavor reflects the journey the water took to get to you, said Lucas Gregory, Ph.D., Texas Water Resources Institute’s assistant director.

“We’ve got the same water here today that we had when time began. So in theory, we’re drinking water that is billions of years old,” Gregory said. “The way water tastes is basically a function of what that water has been exposed to in its more recent history and over the course of its life.”

Municipal drinking water drawn from old aquifers composed mostly of sand frequently has a salty taste. This is the case with water drawn up from the Simsboro formation, part of the Carizzo-Wilcox Aquifer. The Carizzo-Wilcox Aquifer, which stretches diagonally across a large swath of Texas, supplies drinking water for many other parts of Texas.

“The water has been down there hanging out for a long time, basically, and there are some residual salts in those sands,” Gregory said. “That’s why the water has a salty taste.”

Elsewhere in Texas, local water’s flavor has different origins.

Heavily treated surface water sometimes has a mild chlorine taste, especially if you live closer to the point of treatment. Groundwater that has naturally occurring hydrogen sulfide in it, such as near shallow oil fields, smells like rotten eggs, while groundwater with a higher iron content has a slightly metallic taste. Naturally occurring algae and decaying organic matter can give surface water a musty, earthy smell, and traveling through calcium-heavy limestone can give water a sweet aftertaste.

Even the water treatment process itself can cause tastes or odors, said AC Barnett, senior regional technical manager at Inframark Water & Infrastructure Services.

“Disinfected water may retain a faint bleachy odor, for example. Water which resides in pipes for long periods of time through lack of use can develop a stale taste or odor in dead ends on the delivery system,” Barnett said.

The water that both Gregory and Barnett grew up drinking in East Texas, meanwhile, had more iron in it. Gregory said the more iron-heavy water also changed the appearance of things it touched over time.

“If the water sits in a fixture that’s white, such as the bathtub, you’ll get an orange ring where the water sits,” he said. “And if you make a pitcher of iced tea, it’s nice and brown colored at first, but if it sits for a day, it turns black, though it tastes the same.”

Setting the standards

While there are situations where the chemicals in tap water can cause health problems, water having a noticeable taste or smell does not necessarily mean the water is unsafe. The US Environmental Protection Agency (EPA) sets drinking water standards to keep contaminants below a safe level. All public drinking water systems are required to meet those standards.

“Those standards are there to protect human health,” Gregory said. “The science behind them puts those numbers at an acceptable level for the general populace.”

The EPA creates both primary and secondary drinking water regulations. Primary drinking water regulations relate to potential health concerns and require that some contaminants be kept below a certain level. Secondary drinking water regulations, meanwhile, relate to cosmetic or aesthetic effects that aren’t harmful to human health, like water discoloration or a metallic flavor.

Primary drinking water regulations are legally enforceable, while secondary drinking water regulations are not. Some contaminants, like copper, are subject to both primary and secondary drinking water regulations: one level at which they are unhealthy, and one level at which they can be a nuisance but are not dangerous. To learn more about how the EPA develops drinking water standards, read the article “Protecting Drinking Water” in TWRI’s winter 2020 issue of txH2O magazine.

Traveling from treatment to tap

To meet primary drinking water standards — and secondary standards where possible — public water systems treat their water in a number of different ways.

“The treatment process depends on the source you’re dealing with. The dirtier the initial water that you’re dealing with, the more you have to do to it in the treatment process,” Gregory said. “Each step in the process has its own influence on water quality.”

Drinking water that comes from surface water generally requires more treatment, said Shankar Chellam, Ph.D., who is a professor in Texas A&M University’s Zachry Department of Civil and Environmental Engineering.

“Surface water has microorganisms, particles, organic matter, inorganic compounds, lots of things that cause problems with human health,” Chellam said. “They all need to be removed from the drinking water supply prior to human consumption.”

For surface water, the treatment process begins with adding a coagulant, such as iron or aluminum salts. The coagulant helps particles in the water come together, making them large and heavy enough to settle out of the water in a sedimentation basin.

Once the heavier particles have settled out, the water is sent through a filter that removes any leftover smaller particles. Finally, the water is disinfected. Chlorine is the most common disinfectant used in the United States, but chloramine, ozone and ultraviolet light are also used. Because chlorine is both a helpful disinfectant and a contaminant in certain quantities, the EPA maintains standards for using it at a safe level.

Chellam said that the disinfectant is added not only to inactivate microorganisms but also to protect the water from contamination in the distribution system. Having enough disinfectant in the system helps tackle problems that could crop up between the water treatment plant and the point of use.

For groundwater-sourced drinking water, the treatment process is simpler because the ground acts as a natural filter.

“Groundwater is relatively easy — you drill the well and put in the pipeline. That’s the minimum,” Gregory said.

“Groundwater-sourced public drinking water systems still have to meet the same drinking water standards, so if for some reason they aren’t able to meet that standard with just raw water, they’re going to treat it. In most situations where you have a public supplier, they’re going to disinfect.”

If drinking water comes from a private well, the journey to the tap looks a little different. Unlike for public water systems, the state doesn’t test private wells to ensure they meet drinking water standards.

“In Texas, it’s up to the homeowner that has the water well to take the initiative to get the water tested. They have to go collect the sample and take it to the lab,” Gregory said.

The Texas Well Owner Network recommends getting private well water tested annually, as well as after potential contamination events like flooding. Water should be tested at least for E. coli, nitrate and total dissolved solids, but it’s also possible to test for many other potential contaminants. The Texas Well Owner Network periodically offers training courses to help well owners keep their water safe.

Understanding your unique situation

Even if drinking water is coming from a public water system, Gregory said it’s worth being aware of any changes in your tap water. After water is piped as far as the water meter, its quality is out of the public system’s hands.

“The city is only required to deliver that water quality to the meter. Once it's past that meter, it's up to the homeowner,” Gregory said.

He said that homeowners should therefore be aware of what is in their homes and whether their water has changed.

The rotten egg smell of hydrogen sulfide, for example, can sometimes signal a problem. Though the smell can be a result of naturally occurring bacteria in groundwater, Barnett said it can also signify that a chemical reaction is happening inside a water heater.

“If the smell is detected when only the hot water tap is used, draining the hot water heater on a periodic basis can solve the issue,” Barnett said.

“If you have a major concern about your water quality and its impact on you, then the only failsafe way to figure that out is to take a sample of water from the point where you get your drinking water and get it tested,” Gregory said.

For the most part, the public water system can provide answers. Every year, public water systems publish publicly available water quality reports that can help explain local water’s flavor. The reports can be easily downloaded from public water systems’ websites.

Water quality reports help explain the mild saltiness that Gregory and other residents have noticed in the tap water supplied by the Carrizo-Wilcox Aquifer. The EPA’s secondary drinking water regulation for total dissolved solids, which can impart a salty taste, is 500 milligrams per liter of water. Because matching EPA’s secondary drinking water regulations is not required, some states adhere to different standards. Texas’ secondary standard for total dissolved solids is 1000 milligrams per liter of water.  Some cities that get their water from the Carrizo-Wilcox Aquifer have more total dissolved solids than EPA’s secondary drinking water regulation, meaning that though the water may have a noticeable salty taste, it’s not harmful.

For questions not answered by the water quality report, Gregory said the public water system may be able to help with tracking down more information.

“If you’ve got questions beyond the water quality report, they may not have an answer for you, but they should be able to sleuth out the answers you might want,” he said.

Public water quality reports can also be used to help make individual decisions, such as for people with compromised immune systems or specific medical concerns, such as high blood pressure.

“If you are immunocompromised or have some extenuating health circumstance and you suspect that your water may be an issue, I would take that report to your doctor and say, ‘Hey, this is the water I'm drinking. Is this something to be concerned about?’” Gregory said.

But for most people, Gregory said that tap water — with all of its regionally unique flavors — is considered safe to drink per current EPA standards. Notable exceptions do occur, such as in the widely-publicized issues with Flint, Michigan’s water system and other instances of safety standards not being met, but in general EPA standards are designed to ensure broad public safety. And for those who don’t like the flavor or smell or want an added layer of purification, adding a filter at the point of use can help.

“The water meets all the required standards, and public water systems do a great job of delivering high quality water. But if you have a big issue with the taste, then putting in a filter can help,” Gregory said. “It all boils down to preference. That’s the biggest factor in the equation — what do you consider good?”


As a communications specialist for Texas Water Resources Institute, Chantal Cough-Schulze worked with the institute’s communications team writing articles for and editing txH2O magazine and TWRI's news section, developing TWRI multimedia materials and editing reports and education and outreach materials. She also served as the managing editor for the Texas Water Journal.

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