Las Vegas Water: Polluted Or Pristine?

Las Vegas' tap water is a pressing concern for its residents, with many worrying about the quality of the water they drink and use for daily activities. The water in Las Vegas comes primarily from snowmelt in the Rocky Mountains, which flows into the Colorado River and ends up in Lake Mead, where it is treated and distributed to the city. While the Las Vegas Valley Water District maintains that the water meets or surpasses state and federal Safe Drinking Water Act standards, a 2009 study by the Environmental Working Group ranked Las Vegas and North Las Vegas drinking water among the worst in the nation, with 30 pollutants found, including radium, arsenic, and lead. Other contaminants of concern include PFAS, radiation, copper, chromium, and perchlorate.

Contaminants in Las Vegas tap water

About 90% of tap water that residents in Las Vegas drink comes from snowmelt off the nearby Rocky Mountains. After running off the mountains, the water collects in the Colorado River and ends up in Lake Mead, where it’s piped into the city. The remaining 10% comes from a groundwater aquifer sourced from natural precipitation in the Spring Mountains and the Sheep Range.

The tap water in Las Vegas is monitored by the Nevada Bureau of Safe Drinking Water, which is in charge of regulating the city's water supply and ensuring it meets the standards set at the U.S. federal level by the Environmental Protection Agency (EPA). The water delivered by the Las Vegas Valley Water District meets or surpasses all State of Nevada and Federal Safe Drinking Water Act standards.

Despite this, a 2009 study by the Environmental Working Group ranked Las Vegas and North Las Vegas drinking water among the worst in the nation. The drinking water was found to contain traces of 26 contaminants, including radium, arsenic, lead, and uranium. However, it's important to note that the valley's drinking water may have fared poorly in the survey because the agency conducts more robust monitoring and sampling than other municipalities and has more sensitive equipment.

Some of the common contaminants found in Las Vegas tap water include:

• PFAS: Per- and polyfluoroalkyl substances (PFAS) are a category of contaminants that are not yet regulated. They are byproducts of artificial plastics and can end up in water systems. Even trace amounts carry the threat of health hazards.
• Lead: While the levels of lead in the tap water are extremely low, the EPA and other government health organizations dispute that there is any "safe" level of lead in drinking water. Lead enters the water through the corrosion of plumbing pipes containing lead.
• Radiation: This is a concern in Las Vegas, where large amounts of drinking water are exposed to rocks and mineral deposits.
• Copper: Copper pipes are used in Southern Nevada's water system, and copper can leach into drinking water through plumbing. However, the valley's water agencies take steps to protect pipes from corrosion.
• Chromium (hexavalent): Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. It can be present due to industrial pollution or natural occurrences in mineral deposits and groundwater.
• Arsenic: Arsenic is a potent carcinogen and a common contaminant in drinking water, causing thousands of cases of cancer each year in the U.S.
• Chlorate: Chlorate forms as a byproduct of disinfection and can impair thyroid function, making exposure particularly harmful during pregnancy and childhood.

The Las Vegas water monitoring program

One of the key components of the program is the tributary water quality monitoring. This aspect is handled by the Southern Nevada Water Authority and the Clark County Regional Flood Control District. They focus on characterising the water quality in tributaries, such as Duck Creek, Flamingo Wash, and Las Vegas Creek, and quantifying the mass loading of pollutants from urban runoff. Real-time water quality monitoring equipment is employed to collect data at 20-minute intervals, 24/7, logging pH, temperature, dissolved oxygen, and electrical conductance. This data helps in understanding the impact of urban runoff and specific land uses on water quality.

The Las Vegas Valley Water District, a nonprofit organisation, plays a crucial role in the direct management of the city's water sourcing and piping. They are responsible for developing and maintaining the water delivery system and ensuring it meets state and federal Safe Drinking Water Act standards. The Nevada Bureau of Safe Drinking Water, under the Environmental Protection Agency (EPA), regulates the water supply, setting thresholds for the level of chemicals and substances considered hazardous.

Additionally, the Southern Nevada Water Authority's Applied Research & Development Center conducts advanced research to improve water quality and treatment methods. They utilise innovative techniques such as ozonation, filtration, and chlorination to treat water drawn from Lake Mead, ensuring optimal water quality. The Authority has also faced challenges like perchlorate contamination, which has been addressed through cleanup efforts, resulting in significantly reduced perchlorate levels.

While the water supplied to Las Vegas residents is generally considered safe, some concerns have been raised about potential contaminants. These include PFAS, lead, radiation, and copper. The water authorities in the region work diligently to address these issues, implement corrosion control measures, and closely monitor contamination levels to ensure the safety of the drinking water.

The Las Vegas water treatment process

The Las Vegas Valley gets about 90% of its water from the Colorado River, with the remaining 10% sourced from a groundwater aquifer that comes from natural precipitation in the Spring Mountains and the Sheep Range. The Las Vegas Valley Water District, a nonprofit that has been providing the city's water since 1954, is responsible for managing the city's water sourcing and piping.

Water from the Colorado River is collected in Lake Mead, where it is then piped into the city. Water drawn from Lake Mead is sent to either the Alfred Merritt Smith Water Treatment Facility or the River Mountains Water Treatment Facility. The treated water in Las Vegas is safe to drink and meets or surpasses federal drinking water standards, with the Nevada Bureau of Safe Drinking Water regulating the city's water supply and ensuring it meets standards set at the federal level by the Environmental Protection Agency (EPA). The Water District collects and analyzes water samples more frequently than federal regulations require, and also conducts extensive quality control sampling of its water distribution system, including reservoirs and pumping stations.

Despite the treatment processes and regulatory oversight, there are still some concerns about contaminants in Las Vegas' tap water. For instance, PFAS, a recent byproduct of artificial plastics, has been found in water systems, and experts warn that even trace amounts can pose health hazards. Additionally, lead contamination in tap water is a concern, as corroding pipelines can leach lead into the water. As a result, corrosion control measures and close monitoring of lead contamination levels are crucial. Furthermore, radiation in the water supply is an issue that requires careful monitoring, especially given the large amounts of drinking water that come into contact with rocks and mineral deposits.

The Las Vegas Wash is another area of focus for water quality in the region. The Wash is the only drainage channel for the Las Vegas Valley watershed, and its flows have increased significantly due to the valley's rapid growth. This has led to increased erosion, sediments, total suspended solids (TSS), and other constituents, degrading water quality in the Wash and Lake Mead. The Southern Nevada Water Authority and Clark County Regional Flood Control District have implemented a tributary water quality monitoring program to characterize water quality in tributaries and quantify the mass loading of pollutants from urban runoff. This program includes quarterly monitoring of six major tributaries to the Wash, such as Duck Creek, Flamingo Wash, and Las Vegas Creek, to capture major inputs of urban runoff.

The impact of Las Vegas water pollution on Lake Mead

Water pollution in Las Vegas has had a significant impact on Lake Mead, the primary source of water for the city. Lake Mead, located near Boulder City, Nevada, has experienced declining water levels in recent years, with levels plunging to critically low levels in the summer of 2022. While the Las Vegas area drought has not significantly contributed to the lake's declining water levels, the impact of water pollution in Las Vegas on Lake Mead is concerning.

The Las Vegas Wash, the only drainage channel for the Las Vegas Valley watershed, has been a significant source of water pollution flowing into Lake Mead. Over the years, the flows into the Wash have increased due to the rapid growth of the Las Vegas Valley. This has led to a rise in erosion, sediments, total suspended solids (TSS), and other constituents, degrading the water quality in both the Wash and Lake Mead. The increased TSS, derived from sediment erosion, led to the Wash being listed as impaired waters by the Nevada Division of Environmental Protection.

The principal sources of water pollution into the Las Vegas Wash are effluents from sewage treatment plants and waste from power stations. These effluents and waste contain various contaminants that impact the water quality in Lake Mead. Additionally, irrigation return and watershed runoff during precipitation periods also contribute to the pollution levels in the Wash. The impact of these pollutants on Lake Mead has been significant, with reports of deteriorating water quality, unpleasant taste and odours in domestic water supplies, and a reduction in the attractiveness of Las Vegas Bay for recreational activities due to aquatic plants and algae blooms.

To address the water pollution in Las Vegas and its impact on Lake Mead, various monitoring and sampling programs have been implemented. The Las Vegas Wash Coordination Committee (LVWCC) has conducted regular water quality monitoring and sampling of the Wash for over 20 years, working with several partners to coordinate their efforts. Additionally, real-time water quality monitoring programs have been established to collect data on various parameters, including pH, temperature, dissolved oxygen, and electrical conductance. These programs aim to track contamination sources, identify adverse quality factors, and develop strategies to improve water quality in both the Wash and Lake Mead.

The sources of water for Las Vegas

About 90% of tap water in Las Vegas comes from snowmelt in the nearby Rocky Mountains. This snowmelt runs off the mountains, collects in the Colorado River, and ends up in Lake Mead, from where it is piped into the city. Lake Mead, a reservoir on the Colorado River, is an essential source of water for the city, and the Southern Nevada Water Authority has been storing water from the river in the valley's primary aquifer during years of excess. This stored water is intended for community use during times of need, such as extended droughts.

The remaining 10% of water in Las Vegas comes from groundwater aquifers sourced from natural precipitation in the Spring Mountains and the Sheep Range. This groundwater is located a few hundred feet below the land surface and is protected from surface contamination by a layer of clay and fine-grained sediments. However, contaminants such as pesticides and fertilizers have been found in shallow groundwater, typically within 50 feet of the land surface. This shallow groundwater is not used for drinking water, but it is important for managing peak water demands during the summer months, when it can account for up to 25% of the valley's daily water supply.

The quality of water in Las Vegas has been a concern, with reports of deteriorating water quality resulting in taste and odour issues in domestic water supplies. The Las Vegas Wash, the only drainage channel for the Las Vegas Valley watershed, has been a particular focus of water quality monitoring. Increased flows in the Wash due to rapid growth in the valley have led to a rise in erosion, sediments, and total suspended solids (TSS), degrading water quality. Additionally, contaminants such as PFAS, lead, and radiation have been identified in Las Vegas' tap water, raising health concerns among residents.

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