Westminster's backflow test, decoded
Westminster’s program casts one of the wider nets on the Front Range — and files through a portal. Everything below is from the city’s own cross-connection control and backflow prevention page, checked July 2026.
The rules in three lines
- Who: all commercial, industrial, domestic, irrigation, and fire-line services need an approved assembly — and anyone with an auxiliary water supply (a well, a pond) must comply as well.
- When: tested upon installation and annually thereafter, by a certified backflow prevention assembly tester.
- Where it files: through the BSI Online portal, reported to the city’s Cross-Connection Control team.
The well-and-pond clause deserves a highlight
Most cities lead with commercial requirements; Westminster’s page also names auxiliary water supplies — wells and ponds — as triggering the assembly requirement. If your property on the city’s edges keeps an old irrigation well alongside city water, that’s precisely the cross-connection the state’s Regulation 11 exists to control, and precisely the letter that surprises people. (What the letter’s paragraphs mean: the decoder.)
Booking it right
Westminster is a BSI Online city — the tester files through the portal, and portal mechanics are one of the quiet reasons quotes differ (the cost anatomy). Ask the one question that matters: “do you file with Westminster through BSI, and will it land before my due date?” A tester who works this program weekly does it in their sleep — the form below reaches that kind. Program questions go to backflow@westminsterco.gov or 303-658-2477; how neighboring districts differ is mapped in where reports go.
Questions people actually ask
Who needs a backflow assembly in Westminster?
The city's list is broad: all commercial, industrial, domestic, irrigation, and fire-line services require an approved assembly — and customers with an auxiliary water supply, like a well or a pond, must comply too. That last one surprises people on the city's semi-rural edges.
How often does Westminster require testing?
Upon installation and annually thereafter, by a certified backflow prevention assembly tester. The due date on your city notice is the deadline that matters.
Where do Westminster test results go?
The city takes results through the BSI Online portal — your tester submits there. Confirm they filed, not just tested; the program's team is at backflow@westminsterco.gov or 303-658-2477 if something looks wrong.
What's the legal basis for the requirement?
Colorado's Primary Drinking Water Regulation 11 — the state cross-connection-control rule every public water system builds its program on. Westminster's page cites it directly; the same regulation is why every district around Denver runs some version of this program.