Charleston Water System Backflow Testing: Rules and Deadlines

Who must test

Customers whose water use presents a backflow hazard must install a backflow prevention device and have it tested annually by a third-party tester from the Approved Tester List. Source.
Residential customers must have a backflow preventer if they have an irrigation system, a separate irrigation meter or a dock with water service. Source.
Assemblies must be tested by a CWS Approved Tester immediately after installation, relocation, repairs, a maintenance shutoff, and at least once annually. Source.

Notices and deadlines

An annual notification letter is mailed approximately 30 days before the test due date. Source.

How the report is filed

Passing or failing results must reach CWS within seven calendar days after the test, by fax to 843-579-6852 or email to crcfax@charlestoncpw.com with the Field Test Report cover sheet; late or incomplete reports are returned and not accepted. Source.

Tester registration

CWS accepts backflow test results only from testers on its Approved Backflow Tester List. Source.
To be approved a tester must complete SCDES certification, attend a CWS orientation session and follow the Cross Connection Control Program Manual. Source.
Each tester must have a calibrated differential pressure gauge on record with CWS (make, model, serial number and current Certificate of Calibration); tests with gauges not on record are not accepted. Source.

Fees

Testers must recertify every three years to stay on the list; CWS holds quarterly recertification tests and the fee is $80. Source.
CWS charges a $30 annual Backflow Administration Fee for each backflow prevention device. Source.
The annual backflow administration fee is assessed on each assembly; residential irrigation customers are exempt. Source.

Approved testers

CWS publishes a list of companies with employees who are SCDES certified and attended a CWS orientation. names not extracted). Source.

If a test is missed

Failure to comply with program requirements may delay a new connection or result in discontinuance of existing water service. Source.

Program

Charleston Water System's backflow prevention program is administered by its Cross-Connection Control Program. Source.

How to file your backflow test with Charleston Water System

Read your notice. An annual notification letter is mailed approximately 30 days before the test due date.Source.
Book a tester Charleston Water System accepts. See finding a tester below; book early so there is time to repair a failed assembly.
The tester tests the assembly and fills in the test report. A failed assembly is repaired and tested again.
The report is filed. Passing or failing results must reach CWS within seven calendar days after the test, by fax to 843-579-6852 or email to crcfax@charlestoncpw.com with the Field Test Report cover sheet; late or incomplete reports are returned and not accepted.Source.
Fees. Testers must recertify every three years to stay on the list; CWS holds quarterly recertification tests and the fee is $80. Source.
Keep a copy and set a reminder for next year. Set a free test-due reminder.

Finding a tester Charleston Water System accepts

Charleston Water System posts a list of testers it accepts on charlestonwater.com. Open the list. The testers on this site hold a state certificate; check the list or ask the tester whether Charleston Water System accepts them.

Before you book, ask the tester:

Are you registered with Charleston Water System?
Will you send the test report to the utility for me, and how?
When is my report due? The date is on your notice; the tester needs time to test, repair if needed and file.

Other water utilities in South Carolina

Read October 6, 2026. Program page: charlestonwater.com.

Charleston Water System: backflow testing rules