Please check our examination schedule to view open certification examinations. Due to regulations and restrictions surrounding COVID19, our schedule is limited. Continue to check our schedule for updated examination information.

If you are currently eligible to take the BAT Certification written exam, please check AMP's website for current information. 

Emailing WCS at to inquire about BAT exams will be the fastest and most efficient way to get a hold of us during this time.

Backflow Assembly Testers

What's New

In light of concerns concerns surrounding Coronavirus, please check to confirm Green River College Auburn Center is open before heading to your BAT examination appointment.

The purpose of the Backflow Assembly Tester (BAT) certification program is to protect the health of the citizens of the state of Washington. To protect health, state drinking water rules require public water systems to develop and implement Cross-Connection Control programs. Under these programs, some water system customers (property owners) may have to install backflow prevention assemblies. Backflow assemblies must get tested (when installed and annually after that) to make sure they work properly.

Washington State Department of Health (DOH) regulations require anyone who inspects, field tests, maintains and repairs backflow prevention assemblies, devices, and air gaps that protect the public water system to pass the state's certification examination and maintain a valid certificate.

What is backflow?
Backflow occurs when water or other substances flow in the opposite direction than intended allowing contaminants to enter the public water system or consumer's plumbing.

What is a backflow incident?
A backflow incident occurs when biological, chemical, or physical contaminants enter the drinking water supply (under backflow conditions) via unprotected cross-connections. Backflow incidents may cause injury, illness, or death.

What are backflow prevention assemblies?
Backflow prevention assemblies
are mechanical devices installed on water service lines (or at plumbing fixtures) to prevent backflow of contaminants into drinking water through cross-connections.