Water quality tops standards

The quality of tap water in Boulder City exceeds all federal standards according to 2023 Water Quality Report issued by the city last week. The report is issued annually in July each year.

All levels of tracked contaminants were at or below the levels noted in the 2022 report despite the drop in the level of Lake Mead during the reporting period.

While water is delivered to homes and businesses by the city-owned utility, the city does not pump water directly from Lake Mead. Boulder City purchases its water from the Southern Nevada Water Authority, which gets it via intake No. 3 in Lake Mead. This is the same source that provides 90% of the water used in Las Vegas proper. (About 10% of Vegas water is groundwater pumped from an aquifer. Groundwater is used to meet seasonal peak demand and it can account for up to 25% between June and September.)

The water that is drawn from Lake Mead is treated at the Alfred Merritt Smith Treatment Facility on Lakeshore Road. That facility can treat up to 600 million gallons of water a day and it also supplies much of the water used in Las Vegas and Henderson.

Federal water quality standards call for the tracking of more than a dozen possible contaminants. The water used in Boulder City is way below those standards for every contaminant tracked. All levels are at or below the levels reported in 2022.

While Boulder City water is very clean, it is also very hard.

Hardness of water is defined as the amount of mineral content, mostly in the form of calcium and magnesium. As snow and rainwater make its way down the mountains that feed the Colorado River and that eventually end up in Lake Mead, it dissolves these minerals which stay in the water all the way to the end-user’s tap. Boulder City water tests with a hardness of 290 parts per million, making it some of the hardest water in the country. By way of comparison, Phoenix has a 241 rating, Los Angeles has a 127 and San Francisco has a 47. Scottsdale has harder water at a 328 rating.

So why does tap water sometimes appear cloudy? It’s called turbidity and it refers to the overall number of particles in the water, which combined can cause a cloudy appearance, similar to how smoke appears in air. It is measured with a standard called NTUs or Nephelometric Turbidity Units. Lower NTUs indicate high water clarity while higher NTUs indicate lower clarity. EPA standards call for action if 95% of samples are not lower than 0.3 NTUs. Boulder city tap samples were 100% below the 0.3 standard and the highest level in this reporting period was 0.07 NTUs in December of 2022.

While there may be some lead in water coming out of taps in the city this is highly variable and mostly dependent on the pipes and fixtures used in individual buildings. Overall, the samples taken averaged two parts per billion of lead. The EPA standard for action is 15 parts per billion.