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Cross Connection Control

Some common household systems that you connect to water pipes (such as your landscape irrigation system) have the potential to contaminate the water in your home or business.

This scenario is called having a cross connection and you need to take steps to keep each water system separate. If your water from one system mixes with another, it can cause serious illness or injury depending on the type of contaminant. 

How do you know if you have a cross connection?

You have a cross connection when you connect one or more of these household systems to your main water line:  

A child is leaping into a backyard pool toward an adult who is standing in the water, while another child swims nearby. Water splashes around them, and a house with a porch and striped lounge cushions is visible in the background.

A swimming pool is an example of a common cross connection.

  • Irrigation or in-ground sprinkler systems
  • Fire sprinkler systems 
  • Boilers 
  • Swimming pools 
  • Radiant or solar heat systems 
  • Chemical dispensers at sinks or garden hoses 
  • Backup water supplies such as wells and storage tanks 

If you have any of these connected to your home or business water supply, you may need an approved backflow prevention assembly or device to keep your water safe. This device can stop contaminated water from reaching your tap or the water system, and you can often buy one of these devices at most hardware stores. 

The type of common household system you have will determine the type of backflow device you should get (it’s important to know not all backflow prevention systems are the same, and some require specific approvals for you to use them). 

Learn more about cross connection requirements

Your first step is getting a plumbing permit. You get the permit from the authority with jurisdiction over your home or business, which is usually your city or county’s building and permit department. 

While your local jurisdictions issue the permits, Tacoma Water is ultimately responsible for all cross connections. 

Jurisdiction permit information includes:

You need to test your assembly every year. We can take some of the work out of annual testing for you when you sign up for our free reminder program. 

When you sign up, we can automatically let your preferred BAT know when your annual test is coming due. Signing up also means we can discuss the test results with your BAT, which is less work for you. This saves you time and effort because you won’t have to send us the rest results. 

Any Washington-certified backflow assembly tester (BAT) can test your assembly. You can find a list below or you can visit an online database. 

If you select a BAT not on our list, please make sure the tester gives us copies of their current state certification and test equipment calibration certificates. We won’t accept test reports from testers that don’t provide it.  

Sign up to get your assembly tested each year

Sign up to just get your assembly inspected

 

We are legally required to separate your water service from the water main with a reduced pressure backflow assembly or and air gap. The list below includes businesses that need to follow a specific requirement for backflow protection:

A person is spraying water onto the side of a car using a high‑pressure hose at an outdoor car wash. The car’s surface reflects warm sunset light, and water mist is visible around the wheels. The person stands on a wet concrete surface with a hose extended toward the vehicle, while a metal fence and open sky appear in the background.

A car wash is an example of a business that need to follow a specific requirement for backflow protection.

  • Agricultural (farms, dairies, and marijuana production and processing facilities) 
  • Beverage bottling plants 
  • Breweries 
  • Car washes 
  • Chemical plants 
  • Commercial laundries and dry cleaners 
  • Business site that uses reclaimed water and potable water 
  • Film processing facilities 
  • Food processing plants 
  • Hospitals, medical centers, nursing homes, veterinary, medical and dental clinics, and blood plasma centers 
  • Business site with separate irrigation systems that uses the supplier’s water supply, and that the supply has chemicals added 
  • Laboratories 
  • Metal planting industries 
  • Mortuaries 
  • Multi-tenant commercial properties 
  • Petroleum processing or storage plants 
  • Piers and docks 
  • Radioactive material (processing plants or nuclear reactors) 
  • Customer that doesn’t offer us access to evaluate the site, or access restricted areas 
  • Wastewater lift stations and pumping stations 
  • Wastewater treatment plants 
  • Business site with an unapproved secondary water available 

Most of you will need to install (or get help installing) an approved mechanical backflow prevention method to help manage your cross connection. 

Types of approved backflow methods include: 

  • Reduced pressure backflow assemblies (RPBA) 
  • Double check valve assemblies (DCVA) 
  • Pressure vacuum breaker assemblies (PVB/SVBA) 
  • Atmospheric vacuum breakers (AVB) 
  • Air gaps (AG) 

The type of assembly you choose depends on what kind of hazard that’s present, which will either be a potential hazard or actual hazard.  

A small round blue inflatable kiddie pool sits on a grassy lawn, partially filled with water. A green garden hose lies across the grass and into the pool, suggesting it is being filled. The surrounding yard has patches of sunlight and a few bare spots in the grass.

A garden hose dropped in a pool or hot tub creates an “actual hazard’ cross connection.

Here’s an example of these types of hazards: A garden hose is the most common “potential” cross-connection. If you connect the hose to a fertilizer sprayer, or drop it into a pool or hot tub, that’s when it becomes an “actual” cross-connection, changing the hazards present in the situation.

In general, we accept air gaps and reduced pressure backflow assemblies for a system with high hazards. For a low-hazard system, you can likely install double check valve assemblies, pressure vacuum breaker assemblies, and atmospheric vacuum breakers.  

Whatever backflow prevention you (or the homeowner before you) selected must be appropriate for the hazard (the law determines the appropriate backflow prevention for your hazard). It also needs to be listed on the Foundation for Cross-Connection Control and Hydraulic Research Approved Assemblies List.  

We require a Washington-certified BAT to inspect these devices/assemblies after you install them, and then test them each year going forward. If you replace or repair these items, a Washington-certified BAT needs to inspect it again. We require a copy of each test report. 

Three entities can legally install these backflow assemblies: the owner, a licensed plumber, or a full-time employee of the owner. 

  1. How often should I test my backflow prevention assembly? You legally need to test it every year to protect your drinking water from potential contamination. 
  2. Why is this testing necessary and who can do it? The only way to know if your backflow prevention assemblies are working properly — and to keep you and your family safe — is to have a certified backflow assembly tester (BAT) test them. The law says a Washington-certified tester must test your assembly every year (Uniform Plumbing Code Section 603, and state law in Section 246-290-490). 
  3. To get a list of certified testers, email us at backflow@tacoma.gov. If you select a BAT not on our list, please make sure that the tester sends us copies of their current state certification and test equipment calibration certificates. We will not accept test reports from testers who have not provided that information. 
  4. I test my backflow assembly tested every year. Why hasn’t my neighbor heard of the testing requirement? When this happens, the most likely reason is that the neighbor didn’t tell us about their installation, which means we don’t know to send them test notices. It’s also possible that your neighbor worked on their water system without getting the required permits or they installed a non-testable device. However, the neighbor would have had to meet specific installation requirements for that to have had happened.  
  5. I’m not using my irrigation system. Do I still need to test the backflow assembly? Yes. As long as the irrigation system is physically connected to the water system, you still need to test your backflow prevention assembly each year to protect your water from contamination. This won’t apply if you show us there’s a physical disconnect between the irrigation system and the public water supply because you removed the backflow prevention assembly and capped the water supply line. After you cap the line, you must contact our Water Quality department at 253-502-8207 to set up an inspection. Once we verify you did this properly, you don’t need to test your system. 
  6. Who can I call if I have questions about backflow prevention? Please contact us at 253-502-8207 or backflow@cityoftacoma.org. 
  7. What happens if I choose not to test my backflow prevention assembly? We hope you understand that testing is for your protection, but if choose not to test your backflow prevention assemblies as the law requires required, we may take the following enforcement action: 
    • Assess a $100 fee for each assembly not tested and add it to your bill. We will add additional fees of $100d until testing is done correctly. 
    • Install a reduced pressure backflow assembly at your water meter at your expense. 
    • Terminate your water service. 

These are general requirements and may not include specific requirements for your jurisdiction, which you will need for your installation. Please contact Tacoma Water Quality at 253-502-8215 for specific requirements.

  • We must inspect all assemblies once they’re installed or replaced. We will tag inspected and approved assemblies. Customers may request inspections online or by contacting us at 253-502-8215 or backflow@tacoma.gov. We can do most inspections within one business day.
  • If you install, repair, or replace an assembly, you need a Washington-certified BAT to test it.
  • If you install the approved assembly any other way besides horizontally, the USC must approve the installation, regardless of what the manufacturer guidelines say.
  • Make sure assemblies two-and-a-half inches and larger have support stands under the assembly to prevent damage.
  • You’ll need to install the assembly where a spill or relief valve operation won’t present a hazardous condition. For example, you should not install this next to electrical switchgear or panels.
  • Here are the rules to follow if you install the device below ground, here are the rules:
  • In an irrigation box, the top of assembly can’t be deeper than 12 inches from the finished elevation.
  • Assemblies less than two and a half inches must have a minimum of six inches of clearance under the assembly.
  • Assemblies two and a half inches and larger must have a minimum of one foot of clearance under assembly.
  • You need to install a permanent ladder (for safety) for devices you put in vaults
  • You need to snugly install the plugs in each of the test cocks.
  • You need to provide the proper water drainage.
  • All assembly bypasses must have backflow protection equivalent to the assembly you’re bypassing.
  • You must install all above-ground assemblies between one and five feet above the finished floor elevation, unless you install a permanent platform to facilitate testing and maintenance.
  • You can’t install the assembly in in an environment containing toxic, corrosive or hazardous fumes.
  • Don’t install these in crawl spaces or attics.
  • Make sure to install the assembly in a place that protects it from accidental damage.

Reduced Pressure Backflow Assemblies (RPBA)

  • You can’t install an RPBA in a vault or below ground unless Tacoma Water approved it in writing. 
  • You need to set up safe and proper drainage for an RPBA 
  • You need to maintain a minimum one-inch air separation below the relief valve port. You might need larger separations depending on the assembly size. 

Pressure Vacuum Breaker Assemblies (PVBA)

  • You must install a PVBA at least 12 inches above the highest downstream point and install it vertically. 
  • Make sure not to use compressed air fittings on a system that uses a PVBA as backflow protection. 

Atmospheric Vacuum Breakers (AVB)

  • You must install AVBs at least six inches above the highest downstream point and install them vertically. 
  • Make sure not to use compressed air fittings on a system that uses an AVB as backflow protection. 
  • Control valves or shut off valves are not allowed downstream of the AVB. 
  • There must be one AVB for each zone of the system. 

If you are a backflow assembly tester and would like to be included on the tester list we distribute to our customers, please complete and submit the authorized tester participation form. 

The order we list testers is randomly generated each month. Testers remain listed for the current calendar year as long as their test kit calibration information stays current with us.  

Join the Backflow Assembly Tester list

Authority having jurisdiction: This refers to the official, board, department or agency authorized to administer and enforce the Uniform Plumbing Code. In Tacoma, the Public Works Department’s Building and Land Use Services Office is the Authority having jurisdiction, but Tacoma Water is responsible for cross connections. 

Authorized tester: The backflow assembly tester (BAT) is the professional you designate to perform your annual backflow assembly testing. Under our Authorized Tester Program, Tacoma Water automatically sends the annual “your test is test due” notices to the professional you choose. 

Backflow: This is an unwanted reverse water flow (or other substances) coming through a cross connection into the public water system or the consumer’s water system. 

Backflow assembly tester (BAT): A person certified by Washington to test backflow assemblies. See our current list of testers who gave us a copy of their certifications. 

Cross connection: Any actual or potential physical connection between a public water system or the consumer’s water system and any source of nonpotable liquid, solid or gas that could contaminate the potable (drinkable) water supply by backflow. 

Double check valve assembly: A testable assembly that the Washington Department of Health approved. This consists of two independently loaded check valves and two resilient seated shut-off valves. 

Double check detector assembly: A testable assembly that the Washington Department of Health approved. This consists of two approved, double-check valve assemblies arranged in parallel. The bypass assembly is equipped with a meter to detect leakage or water use. 

High health hazard: A cross connection that could impair the quality of water and create a public health hazard through poisoning or spreading disease. 

Low health hazard: A cross connection that could impair the water quality to a degree that does not create a hazard to public health but that negatively affects the water’s appearance, taste, and odor. 

Pressure vacuum breaker assembly: A testable assembly consisting of an internally loaded check valve, an independently operating air inlet valve, and two resilient seated shut-off valves. 

Reduced pressure backflow assembly: A testable assembly that the Washington Department of Health approved that consists of two independently loaded check valves, a spring-loaded differential pressure relief valve, and two resilient seated shut-off valves. 

Cross connection resources

This BAT list is a courtesy to our water customers and doesn’t include all certified backflow assembly testers – only those who gave us a copy of their certifications.  You can also find BAT professionals on this online database. 

We encourage you to get competitive bids.

#1 Veteran Backflow 

  • 253-242-4444 

3:16 Backflow 

  • 253-262-8847 
  • 605265742 

A QRP Backflow Testing 

  • 253-221-3949 
  • qrpbackflowtesting.com 

A1 Backflow DBA Feliks Enterprise 

  • 253-329-3999 

AAA Fire Protection 

  • 800-223-3473 
  • AAAFIFP844PS 

ABT Backflow 

  • 206-707-1775 

Accurate Backflow 

  • 253-988-8300 
  • Evenings and weekends 

Ace Backflow Only 

  • 253-250-1295 
  • ACEBABO770MB 

Advanced Irrigation, Inc 

  • 888-833-6220 
  • ADVANII000PE 

Affordable Washington Backflow Testing 

  • 360-333-2057 

Aloisio Plumbing, Inc 

  • 253-537-9606 
  • ALOISPI003KL 

A-L-S American Landscape Services, LLC 

  • 360-923-2224 
  • ALSAMAL936K9 

American Backflow Services 

  • 503-289-1745 
  • AMERIBS903PA 

Apex Backflow Services 

  • 888-698-2739 
  • ELLIOJ*776J6 
  • apexbacflowservices.com 

Apex Property Solutions LLC 

  • 253-606-8735 
  • WILLIPS792CB 

Backflo Pro’s Inc 

  • 360-951-6130 

Backflow & Irrigation Solutions 

  • 253-391-4258 
  • BACKFIS783C4 

Backflow Biopsy & Contracting LLC 

  • 253-375-9315 
  • BACKFBC803DF 

Backflow VIP, LLC 

  • 253-987-9777 

Backflows Northwest Inc 

  • 425-277-2888 
  • BACKFNI883DN 

Baroumes Backflow LLC 

  • 253-720-0537 
  • BAROUBL787JH 

BAT Lady LLC 

  • 253-514-9935 
  • BATLALL78BS 
  • batlady.wix.com/backflow 

BATMASTER 

  • 425-397-0275 
  • BATMA**944MO 

Blake’s Backflow Service LLC 

  • 509-432-5887 
  • BLAKEBS772L2 

Campbell Underground LLC 

  • 253-606-1301 
  • CAMPBUL848RN 

Campbell’s Backflow Testing 

  • 253-426-2321 
  • CAMPBBL895C5 
  • Commercial & residential 

CERTIFIED BACKFLOW TESTING 

  • 425-427-8889 
  • SEATTTO797NZ 
  • certified-backflowtesting.com 

Coho Backflow Testing LLC 

  • 253-993-0143 
  • COHOBBT762Q5 

Columbia Fire Inc 

  • 206-232-8569 

Cross Connection Services 

  • 253-370-2278 
  • CROSSCS773RG 

DM Backflow Testing 

  • 253-227-8858 
  • DMPLUPT793303 

East Pierce Backflow 

  • 253-380-8380 

Elite Mechanical Services, LLC 

  • 360-489-0717 
  • ELITEMS761BC 

Emerald Fire LLC 

  • 253-857-2056 
  • EMERAFL890MR 

Evergreen Backflow LLC 

  • 253-686-9380 
  • evergreenbackflowllc.com 

Evergreen Fire and Security 

  • 253-627-3794 
  • Commercial Sites 

Fire Solutions NW 

  • 360-479-3473 
  • FIRESSN843QZ 

GCF Backflow 

  • 360-320-9871 

Green Effects Inc 

  • 253-891-9888 

Kelly’s Lawn Salon Inc 

  • 253-606-1000 
  • KELLYLS964OA 
  • Only testing in Puyallup 

Knight Fire Protection 

  • 360-786-8606 

Landscapes By Dan LLC 

  • 253-312-8254 
  • 603211020 

Lane’s Quality Service 

  • 253-229-8386 
  • LANESQS946BC 

Lenny’s Backflow Testing 

  • 253-376-9985 
  • Evenings & weekends 

MacDonald-Miller Facility Solutions 

  • 206-767-7995 

Mario’s Landscaping, Inc 

  • 253-564-4375 
  • MAR101*228B6 

Mark Barnett Backflow 

  • 425-306-1558 

McLaughlin’s Peninsula Backflow Service 

  • 206-890-8337 
  • MCLAUDS960JE 

MCLM LLC 

  • 360-970-5721 
  • MCLMLL*881LD 

Mel’s Backflow Assembly Testing LLC 

  • 253-905-5192 
  • MELSBBA811BP 

Midland Fire & Backflow 

  • 253-386-6395 

Mike’s Backflow Service 

  • 253-345-9658 
  • MIKESBS773JD 

Mike’s Plumbing Repair 

  • 425-765-7827 
  • 601020481 

Mr. Irrigation, Inc 

  • 253-405-1759 

Olympic Landscape & Irrigation 

  • 253-922-7075 
  • OLYMLI206C1 

OneGard 

  • 253-ONE-GARD 
  • One Plan for Home Services 

Outdoor Solutions 

  • 253-310-3522 

P.L.E. Backflow Testing 

  • 253-297-4387 
  • PERSOLE121QW 

Patriot Fire Protection 

  • 253-926-2290 

Rainier Valley Backflow LLC 

  • 253-244-1361 
  • 605382243 
  • rainiervalleybackflow.com 

Redline Mechanical 

  • 360-469-4931 
  • REDLIM*835MM 

Revival Plumbing Solutions LLC 

  • 253-525-1105 
  • REVIVPK761MW 

Rock Mechanical Insulation 

  • 253-431-3751 

Royal Flush Plumbing LLC 

  • 253-882-5533 

Royal Waldock & Associates 

  • 253-549-5573 

SeaTac Fire Protection LLC 

  • 253-341-7132 
  • SEATAFP895RW 

Smith Fire Systems 

  • 253-248-2000 

Sound Backflow Testing 

  • 425-647-7987 

Sound Home Maintenance LLC 

  • 253-223-1554 
  • SOUNDHM928BW 
  • S. Air Force Retired 

Summit Backflow Services 

  • 253-861-9845 
  • SUMMIBS781DP 
  • summitbackflowservices.com 

Tacoma Backflow 

  • 253-484-0000 
  • tacomabackflow.com 

The Sprinkler Guy LLC 

  • 253-391-1254 
  • SPINSG841D2 

Woodland Gardens Construction, Inc 

  • 253-405-0888 
  • WOODLGC924BD 

Zachary Dority 

  • 801-664-4830 

backflowtestswa@gmail.com 

  • If you fill out the report by hand, please use a pen and make sure the report includes your certification number, name, phone number, completion date, and your signature. We can’t accept incomplete reports. 
  • Testers must use the DOH-approved test procedures unless they have alternate procedure that Tacoma Water approved in writing. 
  • The tester must submit the report within 15 days of completing it by fax, email, or mail: 253-502-8721, backflow@cityoftacoma.org, or P.O. Box 11007, Tacoma WA, 98411-0007. 
  • We can’t accept a test report unless we also have a copy of the tester’s current BAT certification card and equipment calibration/verification certificates. As long as these remain valid, testers only need to submit them to us once a year.  
  • If we think your test report is fraudulent, we will investigate and report it to the Ste of Washington Department of Health Certification Offices. If we have found you to submit fraudulent reports in the past, we won’t accept future test reports from you.  

Download a test report

View instructions on how to fill out the test report

Questions? 

To understand how to start this process and determine the correct backflow prevention assembly/device you must use, email us at backflow@tacoma.gov. 

We also have a Cross Connection Program that can help educate you on next steps and the legal requirements you need to follow to install the right backflow prevention method. 

Customers may request inspections online or by contacting us at 253-502-8215 with any questions.