If you live in and around the San Mateo area, you are likely served by the Mid-Peninsula Water District, formerly known as the Belmont County Water District. This water entity is supplied by the San Francisco Regional Water System and relies mainly on spring snowmelt flowing into the Tuolumne River, where it eventually gets stored in the Hetch Hetchy Reservoir.
Several other local watersheds also feed into this system, which means the drinking water in San Mateo can originate from one of several sources. According to the water quality district, although regular testing is done to ensure safe and clean drinking water, some water may be expected to contain a small number of contaminants. Contaminants can range from microbial (such as viruses and bacteria) to pesticides, herbicides, radioactive contaminants, organic chemical contaminants, and inorganic contaminants like salts and metals.
The most common type of contaminants found in local San Mateo water are chloramine and chlorine, which are used to disinfect the water, as well as magnesium, potassium, and sodium, which generally combine to indicate a specific hardness level in the water or the amount of total dissolved solids (TDS) that are present. Chloramine and chlorine are harsh on skin, hair, plumbing parts, and often taste unpleasant. Chloramine is unsafe to drink for those who are undergoing dialysis or are immunosuppressed. Chloramine also kills fish in aquariums. Reverse osmosis drinking water systems will remove chloramine and chlorine from drinking water.
Hard water can present itself in your home as white, cakey residue that is left after a load of dishes are run. Or it can contribute to the tight, itchy feeling that can occur after a warm shower. Hard water destroys appliances, lowers the lifespan of a home’s plumbing, and can make soap less effective. Even if you are in San Mateo and are currently served by the Mid-Peninsula Water District, you can enjoy clean, clear, soft water at home— thanks to water softening treatment.