Fairfax Water: backflow testing rules

Who must test

• Under the Virginia Construction Code, backflow prevention assemblies are tested at installation, right after repairs or relocation, and at least once a year. Source.
• Fairfax Water's outreach to residential customers says Virginia Waterworks Regulations have required annual testing of backflow preventers on in-ground lawn irrigation systems since 1993. Source.

Notices and deadlines

• Each property is assigned a test month; a notice is emailed about 60 calendar days before the due date, and testing must be done no more than 30 days before and not after the due date. Source.

How the report is filed

• The tester or testing company submits the Fairfax County Backflow Assembly Test Report through the county's Cross-Connection Control website within 10 business days of the test; the owner may not be given this task. Source.
• Assemblies that fail must be repaired or replaced and retested within 10 business days of the failed test; only passing reports are accepted. Source.

Tester registration

• Each tester must be certified by the Virginia Department of Professional and Occupational Regulation as a Backflow Prevention Device Worker and give proof to Fairfax County before being authorized. Source.
• Test gauges must be calibrated and certified at least once a year, with no more than 12 months between calibrations. Source.

Approved testers

• Testing may only be done by people on the Fairfax County authorized tester list, which the county maintains and publishes. published Smartsheet web table, not downloaded). Source.

If a test is missed

• Failure to install, maintain, test and get proper test reports submitted is a violation and may lead to additional fees or disconnection of water service. Source.
• After corrective work and fees are paid, Fairfax Water reconnects service and may charge a reconnection fee. Source.

Read October 6, 2026. Program page: fairfaxwater.org.