The tap water supplied by Riverside Public Utilities (RPU) is safe to drink, consistently meeting or exceeding all drinking water quality standards set by both federal and state regulations. RPU is legally required to ensure the water is safe for consumption, and its annual testing results provide evidence of this compliance. The local utility manages the system to provide high-quality water from its source to the customer’s meter.
The Primary Sources of Riverside’s Water Supply
Riverside’s water supply is sourced primarily from local groundwater basins, giving the city a degree of self-sufficiency. The water is drawn from the Bunker Hill and Riverside groundwater basins, which are naturally recharged by local precipitation and river flow. RPU operates 46 potable wells to access this underground supply. RPU maintains access to imported water via the Metropolitan Water District of Southern California (MWD) for emergencies, but has not utilized this supply since 2008, relying instead on robust local groundwater reserves. After extraction, the water undergoes a rigorous treatment process before distribution. RPU operates six treatment plants that utilize technologies like ion exchange, granular activated carbon (GAC) vessels, and membrane filtration. All water sources are blended at a central location to maintain a consistent quality before distribution.
Regulatory Oversight and Annual Safety Reporting
Riverside’s water quality is strictly regulated by two primary authorities: the U.S. Environmental Protection Agency (USEPA) and the California State Water Resources Control Board. These agencies set the Maximum Contaminant Levels (MCLs) that public water systems must meet to ensure public health protection. RPU maintains compliance through an extensive testing and monitoring program. The utility performs over 36,000 to 40,000 water quality tests each year, sampling from the source all the way to the customer tap. Independent, state-certified laboratories test the water for more than 200 regulated and unregulated contaminants, including bacteria, heavy metals, and industrial byproducts. The results are released annually in the Water Quality Annual Report, also known as the Consumer Confidence Report (CCR). This report details all detected contaminants, comparing the levels found in Riverside’s water to the established state and federal standards.
Common Local Concerns: Hardness and Taste
Water Hardness
Despite meeting all safety standards, Riverside water is known for its high mineral content, a common condition in Southern California. Water hardness is caused by dissolved concentrations of calcium and magnesium, typically registering around 202 parts per million (ppm). This hardness is an aesthetic quality concern, not a health one. High hardness levels result in scale buildup on appliances, plumbing fixtures, and dishware. It also reduces the effectiveness of soap and detergents. Many residents choose to install point-of-use or whole-house water softeners to address these mineral deposits.
Taste and Odor
A common aesthetic issue relates to the required disinfection process. RPU adds a trace amount of chlorine to the water supply to prevent the growth of harmful bacteria and viruses within the distribution system. This necessary measure can sometimes result in a noticeable chlorine taste or odor, especially when the water has been sitting stagnant in pipes.
Lead Concerns
Concerns about contaminants like lead are common, but the risk is localized to private plumbing. RPU ensures that the water leaving its treatment plants does not contain lead. However, older homes, particularly those built before 1986, may have lead or galvanized service lines or plumbing fixtures that can leach lead into the water. If the water has been stagnant for several hours, flush the tap for 30 seconds to two minutes before using it for drinking or cooking.