Mountlake Terrace · Snohomish County
Backflow testing in Mountlake Terrace
Mountlake Terrace’s water starts at Spada Lake, is treated by Everett, and reaches the City through Alderwood Water & Wastewater District. The City’s water division handles distribution, and annual backflow testing is required for every assembly in its system.
City of MLT program
How Mountlake Terrace’s backflow program works
The short version, summarized from the utility’s own cross-connection control materials.
Source: City of Mountlake Terrace Water Division · verified October 2026 ↗The City of Mountlake Terrace buys its water through Alderwood Water & Wastewater District, which is supplied by Everett.
State law (WAC 246-290-490) requires annual testing of every backflow assembly by a state-certified tester.
New buildings around the Town Center and light-rail station need initial tests before assemblies go into service.
Report submission
We submit your test report to the City’s water division and send you a copy.
Questions for the utility: (425) 776-1161
On the ground
What we see in Mountlake Terrace
Every city’s housing stock and commercial mix shapes what’s in the meter box.
Station-area multifamily
New mid-rise buildings near the light-rail station come with domestic, fire-line and irrigation assemblies — initial tests at construction and annual tests after.
Services in Mountlake Terrace
Neighborhoods
Serving all of Mountlake Terrace
- Town Center
- Lake Ballinger
- Melody Hill
- Gateway
- I-5 corridor
- Ballinger Park
FAQ
Mountlake Terrace backflow questions
01 Who can test my backflow assembly in Mountlake Terrace?
02 How do backflow test reports get submitted to City of MLT?
03 How much does backflow testing cost in Mountlake Terrace?
04 What if my assembly fails in Mountlake Terrace?
Field test report · next due
Mountlake Terrace test due? We’ll handle it.
Book online in two minutes. We test, repair if needed, and file the report with your water utility — and remind you next year.