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Water Quality


AMWC consistently produces water that meets or exceeds all state and federal drinking water standards.  Water quality samples are regularly taken at the wells and throughout the entire distribution system.  AMWC monitors these samples for all contaminants as required by the USEPA, the Safe Drinking Water Act, and Primary Drinking Water Standards, and follows all guidelines according to the national primary drinking water regulations.  AMWC is required to keep all water analysis results on file for three years.  A summary of water quality sampling results can be found in the Consumer Confidence Report prepared each year by AMWC. A copy of the report can be downloaded in PDF format (by clicking on the Water Quality Report image to the right) or obtained at the AMWC administrative office at 5005 El Camino Real.

Treatment & Disinfection


The majority of AMWC’s groundwater requires no treatment other than chlorination and the “natural filtration” that occurs when the water passes through sand and gravel formations. Water produced from AMWC’s wells is disinfected with chlorine. We maintain positive chlorine residuals both at our wells and throughout the distribution system in order to maintain disinfection levels. We pay particular attention to circulation in our reservoirs to maintain proper chlorine levels there as well.


Pink residue is generally not a problem with water quality. In fact, pink residue is likely a result of airborne bacteria, which produce a pinkish or dark gray film on regularly moist surfaces. Such surfaces include toilet bowls, showerheads, sink drains, and tiles.

Some people have also noted that the pink residue appears in their pet's water bowl, which causes no apparent harm to the pet and is easily cleaned off.

Many experts agree that the bacteria that causes these pink stains is most likely Serratia marcesens, a bacteria which is found naturally in soil, food, and in animals. Serratia, which produce a characteristic red pigment, thrive on moisture, dust, and phosphates and need almost nothing to survive. The pinkish film often appears during or after construction or remodeling, when dust and dirt containing Serratia bacteria are stirred up. Once the bacteria is airborne, it will seek a moist location in which it can grow. Some people have reported that the pink residue only appears during certain times of the year, when their windows are left open for most of the day. This bacteria is present in a number of environments and wind can carry the airborne bacteria or stir up dust in which the bacteria is present. The use of activated carbon filters, which remove chlorine from the water, can make the problem worse. The absence of the normal levels of chlorine in tap water allows Serratia to thrive.

How do I get rid of pink residue?

The best solution to this problem is to continually clean the involved surfaces to keep them free from bacteria. Compounds containing chlorine work best, but keep in mind that abrasive cleaners may scratch fixtures, making them more susceptible to bacterial growth. Chlorine bleach can be used periodically to disinfect the toilet and help to eliminate the occurrence of the pink residue. An easy way to do this is to stir three to five tablespoons of fresh bleach to the toilet tank, flush the toilet to allow the bowl to be disinfected, and add another dose of bleach to the tank as it is refilling. The use of toilet "cakes" containing disinfectant can help keep the problem under control. By keeping bathtubs and sinks wiped down and dry, the formation of pink residue can be avoided.


Hard Water

The high calcium and magnesium levels found in the geologic formation (aquifer) from which AMWC produces its water causes "hardness." While such minerals offer positive health benefits, the hardness can stain fixtures and require greater amounts of detergents than soft water. While hardness can be reduced by the use of water softeners, the brine discharge from the softeners eventually ends up in the groundwater, further increasing its hardness.


Periodically, AMWC receives comments from customers about odors that they detect in the water. The chlorine used for disinfection of the water can sometimes cause an odor. Other times an odor may be the result of low levels of hydrogen sulfide in the water that can impart a sulfur smell. Hydrogen sulfide, in the minute amounts found in the water produced from AMWC wells, is harmless. Normally, customers notice the sulfur odor during periods of peak demand, which is typically summer and early fall when water levels in the wells are lowest. Customers can often reduce odors through the use of household reverse osmosis and carbon filters. Sometimes in-home treatment devices, such as water filters and softeners that are not maintained on a regular basis, can impart an odor into the customer’s tap water. If you have concerns over an odor in your water, please contact AMWC at 466-2428.

Source Water Protection

Activities in and around the wells that produce our water can directly impact its quality. For this reason, AMWC monitors activities that take place in areas that drain toward our wells (i.e., the “watershed”) and conducts daily inspections of the immediate vicinity of each well to identify and eliminate potential sources of contamination or vandalism. Community and private sewer systems, animal waste, leaking underground fuel tanks, industrial discharges, agricultural activities, pesticide/herbicide use, and storm water runoff are possible sources of contaminants to the water supply. However, no contaminant associated with these activities has been detected in the water produced from AMWC’s wells.

Maintaining Water Quality in Buildings with Low or No Use

EPA recommends that building owners and managers take proactive steps to protect public health by minimizing water stagnation during closures and taking action to  address building water quality prior to opening.  

Click HERE to read the complete EPA recommendations. [PDF Format]

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