How does a public water supply (PWS) work?
A water supply has several stages:
- Water source
- This is usually a reservoir or lake
- Some supplies draw groundwater from wells
- Contamination might be introduced here, but the next stage would probably take it out
- Water treatment
- Water from a lake is usually filtered and chlorinated.
- Chemicals are removed and germs are inactivated
- Water storage
- Large tanks or reservoirs may be an inviting target
- Water distribution
- This system could be damaged or contaminated
You can take a virtual tour of the treatment plant in Greensboro, NC, at http://www.greensboro-nc.gov/water/Supply/treatment.htm
Water is a national security issue