SENTINEL GAP WATER ASSN

Washington — Community Water System — PWSID: WA5376620

System Information

PWSID	WA5376620
System Name	SENTINEL GAP WATER ASSN
System Type	Community Water System
Water Source	Ground Water
Activity Status	Active
Owner Type	Private
EPA Region	10
Serves School	No
Wholesaler	No
First Reported	Feb 7, 1981
Last Reported	Dec 11, 2025

Location & Contact

State	Washington
City	Mattawa
ZIP Code	99349
Address	706 Desert Aire Dr SW
Organization	SENTINEL GAP WATER ASSN
Phone	—

Population & Service

Population Served	226
Service Connections	68

Drinking Water Violations (52)

This water system has 52 violations recorded in the EPA SDWIS database.

Begin Date	End Date	Contaminant	Category	Health-Based	Major	Measured	Federal MCL	State MCL	Status	Return to Compliance	Rule
Nov 1, 2023	Nov 30, 2023	Revised Total Coliform Rule	MON	No	Yes	—	—	—	Resolved	Nov 30, 2023	Revised Total Coliform Rule
Jul 1, 2023	—	Consumer Confidence Rule	Other	No	No	—	—	—	Resolved	Sep 20, 2023	Consumer Confidence Rule
Sep 1, 2022	Sep 30, 2022	Revised Total Coliform Rule	MON	No	Yes	—	—	—	Resolved	Sep 30, 2022	Revised Total Coliform Rule
Aug 1, 2017	Aug 31, 2017	Revised Total Coliform Rule	MON	No	Yes	—	—	—	Resolved	Aug 31, 2017	Revised Total Coliform Rule
Sep 1, 2015	Sep 30, 2015	Coliform (TCR)	MR	No	No	—	5% of samples	—	Resolved	Sep 30, 2015	Total Coliform Rule
Jul 1, 2014	—	Consumer Confidence Rule	Other	No	No	—	—	—	Resolved	Aug 22, 2014	Consumer Confidence Rule
Jul 1, 2012	—	Consumer Confidence Rule	Other	No	No	—	—	—	Resolved	Oct 1, 2012	Consumer Confidence Rule
Jun 1, 2006	Jun 30, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Jun 30, 2006	Total Coliform Rule
May 1, 2006	May 31, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	May 31, 2006	Total Coliform Rule
Apr 1, 2006	Apr 30, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Apr 30, 2006	Total Coliform Rule
Mar 1, 2006	Mar 31, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Mar 31, 2006	Total Coliform Rule
Feb 1, 2006	Feb 28, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Feb 28, 2006	Total Coliform Rule
Jan 1, 2006	Jan 31, 2006	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Jan 31, 2006	Total Coliform Rule
Oct 1, 2005	Oct 31, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Oct 31, 2005	Total Coliform Rule
Sep 1, 2005	Sep 30, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Sep 30, 2005	Total Coliform Rule
Aug 1, 2005	Aug 31, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Aug 31, 2005	Total Coliform Rule
Jul 1, 2005	Jul 31, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Jul 31, 2005	Total Coliform Rule
Jun 1, 2005	Jun 30, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Jun 30, 2005	Total Coliform Rule
May 1, 2005	May 31, 2005	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	May 31, 2005	Total Coliform Rule
Mar 1, 2005	Mar 31, 2005	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Mar 31, 2005	Total Coliform Rule
Sep 1, 2004	Sep 30, 2004	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Sep 30, 2004	Total Coliform Rule
May 1, 2004	May 31, 2004	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	May 31, 2004	Total Coliform Rule
Sep 1, 2003	Sep 30, 2003	Coliform (TCR)	MR	No	No	—	5% of samples	—	Archived	Sep 30, 2003	Total Coliform Rule
Sep 1, 2000	Sep 30, 2000	Coliform (TCR)	MR	No	Yes	—	5% of samples	—	Archived	Sep 30, 2000	Total Coliform Rule
Oct 1, 1999	Oct 31, 1999	Coliform (TCR)	MR	No	Yes	—	5% of samples	—	Archived	Oct 31, 1999	Total Coliform Rule
Apr 1, 1999	Apr 30, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Apr 30, 1999	Total Coliform Rule
Apr 1, 1999	Apr 30, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Apr 30, 1999	Total Coliform Rule
Apr 1, 1999	Apr 30, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Apr 30, 1999	Total Coliform Rule
Apr 1, 1999	Apr 30, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Apr 30, 1999	Total Coliform Rule
Mar 1, 1999	Mar 31, 1999	Coliform (TCR)	MR	No	Yes	—	5% of samples	—	Archived	Mar 31, 1999	Total Coliform Rule
Mar 1, 1999	Mar 31, 1999	Coliform (TCR)	MR	No	Yes	—	5% of samples	—	Archived	Mar 31, 1999	Total Coliform Rule
Feb 1, 1999	Feb 28, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Feb 28, 1999	Total Coliform Rule
Feb 1, 1999	Feb 28, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Feb 28, 1999	Total Coliform Rule
Feb 1, 1999	Feb 28, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Feb 28, 1999	Total Coliform Rule
Feb 1, 1999	Feb 28, 1999	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Feb 28, 1999	Total Coliform Rule
Oct 1, 1998	Oct 31, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Oct 31, 1998	Total Coliform Rule
Oct 1, 1998	Oct 31, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Oct 31, 1998	Total Coliform Rule
Oct 1, 1998	Oct 31, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Oct 31, 1998	Total Coliform Rule
Oct 1, 1998	Oct 31, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Oct 31, 1998	Total Coliform Rule
Jun 1, 1998	Jun 30, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Jun 30, 1998	Total Coliform Rule
Jun 1, 1998	Jun 30, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Jun 30, 1998	Total Coliform Rule
Jun 1, 1998	Jun 30, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Jun 30, 1998	Total Coliform Rule
Jun 1, 1998	Jun 30, 1998	Coliform (TCR)	MCL	Yes	No	—	5% of samples	—	Archived	Jun 30, 1998	Total Coliform Rule
Oct 1, 1979	Oct 31, 1979	Nitrate	MR	No	No	—	10 mg/L	—	Archived	Oct 31, 1979	Nitrate Rule
Oct 1, 1979	Oct 31, 1979	Fluoride	MR	No	No	—	4.0 mg/L	—	Archived	Oct 31, 1979	Inorganic Chemicals
Oct 1, 1979	Oct 31, 1979	Selenium	MR	No	No	—	0.05 mg/L	—	Archived	Oct 31, 1979	Inorganic Chemicals
Oct 1, 1979	Oct 31, 1979	Chromium	MR	No	No	—	0.1 mg/L	—	Archived	Oct 31, 1979	Inorganic Chemicals
Oct 1, 1979	Oct 31, 1979	Gross Alpha, Excl. Radon and U	MR	No	No	—	15 pCi/L	—	Archived	Oct 31, 1979	Radionuclides and Revised Rad Rule
Oct 1, 1979	Oct 31, 1979	Arsenic	MR	No	No	—	0.010 mg/L	—	Archived	Oct 31, 1979	Arsenic Rule
Oct 1, 1979	Oct 31, 1979	Mercury	MR	No	No	—	0.002 mg/L	—	Archived	Oct 31, 1979	Inorganic Chemicals

About This Water System

Public water system data comes from the EPA Safe Drinking Water Information System (SDWIS). Systems with violations must notify customers. Contact your water utility for the latest annual water quality report.

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