By Michael Sims
In case you don’t know:
From Health & Safety Code Section 116275(h) – (k), (o), (z), 355,356:
- (h) “Public water system” means a system for the provision of water for human consumption through pipes or other constructed conveyances that has 15 or more service connections or regularly serves an average of at least 25 individuals daily at least 60 days out of the year. A public water system includes the following:
- (1) Any collection, treatment, storage, and distribution facilities under control of the operator of the system that are used primarily in connection with the system.
- (2) Any collection or pretreatment storage facilities not under the control of the operator that are used primarily in connection with the system.
- (3) Any water system that treats water on behalf of one or more public water systems for the purpose of rendering it safe for human consumption
- (i) “Community water system” means a public water system that serves at least 15 service connections used by yearlong residents or regularly serves at least 25 yearlong residents of the area served by the system.
- (j) “Noncommunity water system” means a public water system that is not a community water system.
- (k) “Nontransient noncommunity water system” means a public water system that is not a community water system and that regularly serves at least 25 of the same persons over six months per year.
- (o) “Transient noncommunity water system” means a noncommunity water system that does not regularly serve at least 25 of the same persons over six months per year.
- (z) “Small community water system” means a community water system that serves no more than 3,300 service connections or a yearlong population of no more than 10,000 persons.
Federal UCMR
The federal UCMR program involves monitoring primarily by large PWS, although certain smaller systems may be required to participate. USEPA develops the UCMR lists of chemicals which are sampled over several years. USEPA identifies the systems that will participate, as well as sampling points and analytical methods to be used. For more Information, see the USEPA’s website on UCMR program (https://www.epa.gov/dwucmr).
The federal UCMR sampling programs over the past several decades have focused on the following chemicals.
UCMR 5 (2023-2025) Assessment Monitoring
- Twenty-nine perfluorinated compounds (the 6 from UCMR 3)
- One metal/pharmaceutical (lithium)
For more information, see USEPA’s website on UCMR5 (https://www.epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule)
Excerpted from the State Water Resources Control Board – 2025 Safe Drinking Water Plan