> Home > Scottsdale Water Resources Division > Water Quality > Drinking Water > Drinking Water Hot Topics

Drinking Water Hot Topics


Get your questions on drinking water testing answered here:

Disinfection Byproducts:
Disinfection byproducts (DBPs) are formed as a result of a chemical reaction between chlorine and naturally occurring organic matter in the water.  In order to minimize the formation of disinfection byproducts, levels of Total Organic Carbon (TOC) are reduced through the treatment process primarily through the use of granular activated carbon (GAC) adsorption. TOC levels are monitored before and after water treatment to ensure adequate removal of TOC.  Further, chlorine levels are carefully controlled so that disinfection is effective while minimizing levels of disinfection byproducts. 
THM Fact Sheet - May 2008 (pdf/49kb/2pp

Groundwater in Scottsdale and throughout Arizona contains naturally occurring arsenic. Arsenic is also present in surface water originating from the Verde River watershed. Scottsdale operates three arsenic treatment facilities that remove arsenic from groundwater.  The Chaparral Water Treatment Plant also has arsenic treatment capabilities for water received from the Verde River (via Salt River Project). The water treated at these facilities is monitored weekly or more frequently to ensure that arsenic levels do not exceed the regulatory limit of 10 parts per billion (ppb).

Lead and Copper
The primary source of Lead and Copper in drinking water is not the source water, but rather household plumbing fixtures and pipes. Lead and copper may leach from faucets or plumbing components into water when the water stands motionless for several hours.  Leaching may also occur in copper pipes joined with lead-based solder.  Because the water in your pipes can pick up these metals, installation of lead-containing solder, pipes, and fittings was banned in 1986.  City of Scottsdale is responsible for providing high quality drinking water but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking.

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline (800-426-4791) or at  www.epa.gov/safewater/lead.


Cryptosporidium is a microbial pathogen found in surface water throughout the United States.  Ingestion of Cryptosporidium may cause cryptosporidiosis, a gastrointestinal illness.  Cryptosporidium must be ingested to cause this illness, and it may be spread through means other than drinking water.  As required by federal regulation, Scottsdale’s source water has been extensively monitored for Cryptosporidium to ensure that our current treatment technologies are sufficient to remove this pathogen. The city continues to conduct voluntary monitoring for Cryptosporidium in our source water.

Pharmaceuticals and EDCs:

Pharmaceuticals and endocrine disrupting compounds (EDCs) in our drinking water supply are an emerging issue throughout the country.  As you may recall, water in all of its forms is part of a cycle.  All the water that has ever existed on earth still remains today in one form or another.  Pharmaceuticals consumed by humans are not always fully utilized and broken down and therefore are excreted from our bodies through urine into our wastewater collection system.  Although standard wastewater treatment practices remove most pharmaceutically active compounds, some persist and may eventually end up in a drinking water supply. 

At this time little is known about the health effects of low-level exposure to pharmaceuticals and other EDCs, and there are no regulatory guidelines set forth by the EPA.  As health information becomes available or these contaminants become regulated, Scottsdale will be prepared to meet regulations and maintain a safe drinking water supply.

Musty Taste and Odor:

Algae blooms that occur in the lakes, reservoirs, and canals that store and transport our source water create a musty, earthy smell in the water. As the algae decays, it emits a pungent odor that is picked up by the water.  During the peak periods (late summer to early fall), these odors can persist even after the water has been treated to drinking water standards.  Scottsdale’s use of granular activated carbon (GAC) adsorption removes most of the odor-causing compounds; however some people are more sensitive to these odors and will continue to find the smell and taste of the water objectionable during these periods.  To lessen the musty smell in water, chill your water prior to use or add a slice of lemon or other fragrant fruit to your water glass.