Glendale Water Is Very Hard — Here's What It Costs You Each Year

Why Is Glendale Water So Hard?

Glendale water hardness is 21 grains per gallon (GPG), which is 358.6 parts per million (ppm). That puts it squarely in the “very hard” category, and it’s roughly three times the USGS national average of about 21 GPG. You’re not imagining it if your glasses spot, your showerhead clogs, and your soap barely lathers. That’s what 21 GPG does.

Now, here’s the part that surprises a lot of people. Glendale sits in the Los Angeles basin, and the city’s supply is a blend that leans heavily on surface water imported from hundreds of miles away. The Colorado River and the State Water Project (which pulls from the Sacramento-San Joaquin Delta) are the big players feeding Southern California’s Metropolitan Water District, and Glendale buys into that system. That water is surface water, plain and simple. It’s not coming from a deep limestone aquifer under your feet.

So where does all the hardness come from if it’s not groundwater? It’s the journey. The Colorado River starts in the Rocky Mountains, where snowmelt runs over and through granite, basalt, and volcanic rock. Those rocks are relatively low in calcium and magnesium, but that’s not the whole story. As the river cuts through the Colorado Plateau, it passes through massive sedimentary formations, including limestone and dolomite. Rainwater, slightly acidic from dissolved carbon dioxide, chews into that calcium carbonate rock and carries the dissolved minerals downstream. By the time the water reaches Lake Mead and the aqueducts that send it west, it has picked up a serious mineral load.

The State Water Project water takes a different path but ends up in a similar place. Northern California rivers drain the Sierra Nevada, and while the granite there doesn’t dissolve easily, the water still collects minerals as it travels through the Sacramento-San Joaquin Delta. The delta is a mixing zone where river water meets tidal influence and passes through ancient marine sediments. Those sediments are rich in calcium and magnesium from millions of years of shell and mineral deposits. The water that eventually reaches Glendale’s taps has been in contact with mineral-bearing rock and soil for a long, long time.

There’s another layer to this. Southern California’s water districts don’t just send one source to every customer. They blend Colorado River water, State Project water, and sometimes local groundwater depending on the season, the drought conditions, and what’s available. That blending means Glendale’s hardness can fluctuate a bit throughout the year, but the overall picture stays the same. This is mineral-heavy surface water, treated and piped across the desert, and it arrives with its dissolved calcium and magnesium intact. Water treatment plants remove sediment, pathogens, and many contaminants, but they don’t remove hardness. That’s not a failure of the treatment process. It’s by design, because the EPA doesn’t regulate hardness as a health hazard. It’s classified only as an aesthetic issue under the Secondary Maximum Contaminant Level.

How Glendale Compares to Nearby Cities

Glendale’s 21 GPG puts it on the higher end for the Los Angeles area, but it’s not an outlier. The reason is simple: most cities in the region drink from the same imported surface water system. Burbank, Pasadena, and Los Angeles all pull from the Metropolitan Water District’s imported supplies to varying degrees. If you live in Burbank and your water feels similar to Glendale’s, you’re not imagining that. You’re both drawing from the same Colorado River and State Project water sources.

That said, there are real differences between neighboring cities, and they come down to local blending decisions. Some cities mix in more local groundwater, which in the San Fernando Valley can be quite hard on its own, sometimes harder than the imported surface water. Others lean more heavily on one imported source over another. Pasadena, for instance, has its own groundwater wells in the Raymond Basin in addition to imported water, so its hardness can vary depending on how much well water is in the mix at any given time.

Los Angeles is a special case because it’s huge and pulls from multiple sources. The city gets water from the Los Angeles Aqueduct (which brings Sierra Nevada runoff down the Owens Valley), plus imported State Project water, plus local groundwater. That Owens Valley water is notably softer than Colorado River water because it flows mostly over granite. So a household in the San Fernando Valley portion of LA might see softer water than a household in Glendale, even though they’re only a few miles apart. It all depends on which reservoir and which blend is feeding that particular neighborhood on that particular day.

The practical reality for Glendale residents is this: you’re dealing with water that’s consistently very hard, and it’s not going to soften up on its own. The USGS notes that roughly 85% of American households have hard water, but at 21 GPG, you’re well above what most of the country deals with. According to the WQA and Battelle Memorial Institute’s 2010 detergent study, soft water can cut laundry detergent use by up to 50% and dish soap by up to 70%. And the Battelle Memorial Institute and WQRF’s 2009 research found that every 5 GPG of hardness costs a gas water heater about 4% in efficiency for a typical 50-gallon-per-day household. The DOE adds that just a quarter-inch of scale can slash water heater efficiency by up to 40%. Hard water also shortens water heater service life by roughly 30-50%. Those numbers add up fast at 21 GPG, and that’s before you count the soap scum, the spotted dishes, and the extra detergent you’re pouring down the drain every week.

How does Glendale stack up against the rest of California? It's very hard at 21 GPG — Berkeley, Hayward, and San Francisco sit nearby with different numbers. See the full hardest-water ranking for context.

See where Glendale sits on the California water hardness map →

Want the broader explainer on what hardness actually is and how it behaves? Read hard water vs. soft water, explained.