Is Boulder City tap water safe to drink?

A single plant and a city network

Boulder City buys its water from the Southern Nevada Water Authority. The authority draws it from Lake Mead through Intake No. 3; the city gives the lake’s inflows as 97 percent Colorado River, 1.45 percent Virgin River, 1.5 percent Las Vegas Wash and a trace from the Muddy River. All of it is cleaned at one plant, the Alfred Merritt Smith Water Treatment Facility, which hits incoming water with ozone and chlorine, runs it through direct filtration, disinfects it a second time and adjusts it to limit pipe corrosion before sending it on.

Two details in the report are specific to this supply. Nevada normally makes plants wash their filters on restart after downtime; the state gave the Alfred Merritt Smith plant a variance after testing showed no harm to water quality without it. And the state’s assessment of the intake rated it at moderate risk for organic, microbial and radioactive contaminants and high risk for inorganic ones, based on land use around the lake. The report adds that even before treatment, intake water meets every legal limit except for the microbes found naturally in surface water.

Boulder City’s 2025 results

The first half of the table is the treatment plant’s water as it enters the city; the second half is what the city measured in its own pipes and at customers’ taps.

The line to watch is total trihalomethanes: 68 ppb at the worst sampling site’s running average, the closest any reading came to its limit (80). These form after chlorine is added, so they are measured in the pipes rather than at the plant. Haloacetic acids, the other byproduct group, peaked at 32 against 60.

For lead and copper the city used 2024 samples, because yearly testing wasn’t required: 31 home taps, with lead at 2.0 ppb at the 90th percentile (action level 15) and copper at 0.92 ppm (action level 1.3). One copper sample topped the action level.

One printing quirk: the city’s table gives haloacetic acids in ppm. The 60 limit for that group is in parts per billion, so we show ppb, as the Henderson and water district reports do.

Boulder City chlorine concentration in drinking water

Free chlorine in the city’s pipes ran from not detected up to 1.7 ppm in 2025, and its highest running yearly average was 0.91 ppm. The maximum allowed is 4.0. Chlorine keeps the water free of microbes on its way through the network, and the city says it is probably what you taste when tap water tastes of something. For the chlorine taste, the Las Vegas Valley Water District, which handles the same lake water, suggests a pitcher of tap water in the fridge for a few hours or an inexpensive activated carbon filter.

Boulder City water hardness

The city gives its water’s average hardness as approximately 17 grains per gallon, or 290 parts per million, and that is the number to dial into a softener. It explains the hardness simply: on the way down from the mountains the Colorado River dissolves calcium and magnesium from its banks, those minerals stay in the water to your tap, and they’re left behind as white residue when water evaporates. Because the figure appears only in the report’s questions section and not in its tables, treat it as a guide. For sizing and salt at 17, see the Boulder City water softener guide.

Lead precautions from the city’s report

Boulder City’s advice applies to any home with older fixtures: use only cold water for drinking, cooking and baby formula; remember that boiling does not remove lead; and if water has sat for hours, run the tap, take a shower or do a load of laundry before drinking. A filter certified to reduce lead works too. The city will test your water or share its service line inventory if you call. Pregnant people and parents of infants should also ask their doctor.

Want the minerals out of your drinking water as well? Our water filtration options guide lays out what each type of filter removes.

Neighbours and other systems

Henderson’s tap water results come from the same lake and partly the same plant, but the city tests its own pipes and gives its own hardness. If you’re unsure which supplier serves an address, check the water hardness by ZIP code table.

Sources for this page

• City of Boulder City · annual water quality report · 2026 (2025 data; lead and copper 2024) · checked 22 October 2026 · every figure in the results table, no violations, water source and Lake Mead inflows, treatment steps, filter variance, intake assessment, chlorine taste, hardness, lead advice, home treatment devices.
• Las Vegas Valley Water District · water quality questions-and-answers page · current, checked 22 October 2026 · fridge pitcher and carbon filter tips for chlorine taste.
• U.S. Geological Survey · Water Science School page on hardness · undated (checked 22 October 2026) · “very hard” above 180 mg/L.