Backflow Testing in Washington
Backflow Testing across Washington: the 500 ZIP codes and 284 cities we route calls in, and who licenses plumbers in the state.
Free to homeowners in Washington — the contractor pays us for the introduction, you never do.
Who has to test
Our backflow testing coverage in Washington runs to 500 ZIP codes in 284 cities. In a state that mixes large systems with small ones, a testing duty that is routine on one side of a county line can be unknown on the other, and the deadline a premises is held to is whichever its own water supplier sets.
Source: coverage area as published by our call partner; place and county names from the US Census Bureau.
We route backflow testing calls in 500 ZIP codes across 284 Washington cities, in 28 counties.
What this site is
CrossConnect is a referral service, not a contractor. We connect property owners and managers with independent contractors. Backflow assembly testing is normally restricted to testers holding a specific certification and using calibrated equipment, and the report usually has to reach your water purveyor — ask to see the certification and ask who files the report. We carry out no testing, we certify nobody, we do not set prices, and we never charge callers anything. Nothing here selects a device for any installation or states that any assembly is passing.Checking a credential in Washington
Washington licenses are issued by the Washington State Department of Labor and Industries, which publishes a public search you can use before work begins.
18 of the 28 Washington counties we cover, from the top of the alphabet
- Adams County 1 ZIP code
Othello - Benton County 10 ZIP codes
Kennewick, Richland, Benton City, Paterson, Plymouth, Prosser, West Richland - Chelan County 7 ZIP codes
Cashmere, Chelan Falls, Dryden, Malaga, Monitor, Peshastin, Wenatchee - Clark County 22 ZIP codes
Vancouver, Amboy, Battle Ground, Brush Prairie, Camas, La Center, Ridgefield, Washougal, Yacolt - Cowlitz County 11 ZIP codes
Ariel, Carrolls, Castle Rock, Cougar, Kalama, Kelso, Longview, Ryderwood, Silverlake, Toutle, Woodland - Douglas County 1 ZIP code
East Wenatchee - Franklin County 6 ZIP codes
Pasco, Connell, Eltopia, Kahlotus, Mesa - Grant County 1 ZIP code
Mattawa - Grays Harbor County 7 ZIP codes
Cosmopolis, Elma, Malone, McCleary, Montesano, Oakville, Satsop - Island County 6 ZIP codes
Camano Island, Clinton, Freeland, Greenbank, Langley, Oak Harbor - King County 117 ZIP codes
Seattle, Bellevue, Kent, Renton, Auburn, Federal Way, Kirkland, Redmond, Issaquah, Sammamish, Woodinville, Baring, Black Diamond, Carnation and 15 more - Kitsap County 2 ZIP codes
Olalla, Port Orchard - Kittitas County 10 ZIP codes
Cle Elum, Easton, Ellensburg, Kittitas, Ronald, Roslyn, Snoqualmie Pass, South Cle Elum, Thorp, Vantage - Klickitat County 1 ZIP code
Bickleton - Lewis County 21 ZIP codes
Centralia, Chehalis, Cinebar, Curtis, Doty, Ethel, Galvin, Glenoma, Mineral, Morton, Mossyrock, Napavine, Onalaska, Packwood and 7 more - Lincoln County 1 ZIP code
Reardan - Mason County 8 ZIP codes
Allyn, Belfair, Grapeview, Lilliwaup, Matlock, Shelton, Tahuya, Union - Pend Oreille County 1 ZIP code
Newport
10 more Washington counties are inside the coverage area and are not listed here. If your ZIP code is in Washington, the call reaches a contractor.
What that coverage looks like
The 28 counties in our Washington footprint are served by many separate water suppliers, and each one decides which premises must test and how often. King County, with 121 covered ZIP codes, is the largest single block of them; Seattle alone holds 60.
How a backflow testing job goes
A backflow test is a scheduled job that ends in a document. The assembly is isolated, the differential across it is measured, the result is written down, and the report goes to whoever requires it. A failed test means a repair or a rebuild and then a re-test; it does not mean the premises closes that day.
What the call asks about backflow testing
- What kind of premises it is and what is connected to the supply — irrigation, a boiler, a fire line, a commercial kitchen.
- Who is asking for the test: a water supplier, a health department, or a landlord.
- Whether there is an existing assembly with a serial number on it, and when it was last tested.
Every Washington city we route in
78 cities, ordered by the share of buildings with twenty or more units. Containment assemblies are required building by building, and that is where the buildings are. Each page carries that city’s own numbers and the ZIP codes we route there.
- Seattle 34%
- Bellevue 29%
- Mercer Island 24%
- Redmond 24%
- Kirkland 19%
- Mountlake Terrace 18%
- Lynnwood 18%
- Kenmore 17%
- Milton 16%
- Everett 16%
- Renton 16%
- Issaquah 16%
- Bellingham 15%
- Edmonds 14%
- Bothell 13%
- Tacoma 12%
- Spokane 12%
- Richland 12%
- Vancouver 12%
- Mukilteo 11%
- Kent 11%
- Federal Way 10%
- Woodinville 10%
- Ellensburg 10%
- Lacey 10%
- Longview 10%
- University Place 10%
- Lakewood 10%
- Wenatchee 10%
- Cheney 10%
- Auburn 10%
- Burlington 9%
- Kennewick 9%
- Liberty Lake 9%
- Fife 9%
- Prosser 8%
- Veradale 8%
- Mount Vernon 8%
- Centralia 8%
- Walla Walla 8%
- Medical Lake 7%
- Olympia 7%
- Woodland 7%
- Sumner 7%
- Ferndale 7%
- Dupont 6%
- Yakima 6%
- Puyallup 6%
- Chehalis 6%
- Sunnyside 6%
- Pasco 6%
- East Wenatchee 5%
- Selah 5%
- Arlington 5%
- Marysville 5%
- Stanwood 4%
- Gig Harbor 4%
- Castle Rock 4%
- Camas 4%
- Othello 4%
- Monroe 4%
- North Bend 4%
- Battle Ground 4%
- Lynden 4%
- Kelso 3%
- Montesano 3%
- Sammamish 3%
- Sedro Woolley 3%
- College Place 3%
- Toppenish 3%
- Cle Elum 3%
- Greenacres 2%
- Anacortes 2%
- Deer Park 2%
- Rochester 2%
- Ridgefield 2%
- Enumclaw 2%
- Grandview 2%
Before you call
A test is a scheduled job with a report at the end of it, not a repair. What the report has to show, and who it goes to, are on the pages above.
