Fire Flow Tests

Fire flow tests provide actual pressure and flow data measured at specific fire hydrants within the County’s water distribution system. This data is used in assessing the pressure and flow available for fire protection and in sprinkler system design to ensure public safety.

  • The “test” fire hydrant (FH) is typically the hydrant closest to the subject property’s connection point to the County’s water system.
  • The static pressure is the system pressure measured at the “test” FH under normal flow conditions
  • The “flow” FH is typically an adjacent FH located on or near the same water main as the “test” FH.
  • The “flow” FH is slowly opened and the amount of flow at the “flow” FH is measured while the residual pressure at the “test” FH is measured.
  • The difference between the static and residual pressures measured at the “test” FH indicates the drop in pressure that occurs when the measured flow is imposed on the system.

Sprinkler designers utilize the static and residual pressures and the measured flow recorded during a fire flow test to design the sprinkler system for the subject property. Proposed sprinkler system designs are reviewed by the fire protection engineers in the Permit Center. The sprinkler system design must be approved by the engineers at the Permit Center before a building permit can be issued. Inspections must be done by the Fire Marshall’s Office before the building occupancy is permitted. This review process ensures that sprinkler systems are properly designed and that adequate fire protection is available to ensure public safety.

Properties north and west of Deep Run, from its crossing of the CSX Railroad (northwest of the intersection of Dorsey Road and O’Connor Drive) to its confluence with the Patapsco River, are in Howard County. Properties northwest of the CSX Railroad, from its crossing of Deep Run to its crossing of the Patuxent River, are in Howard County.

Annapolis City has its own Utility System. Before requesting a fire flow test, please check to see which jurisdiction provides water to your location. Click here for a map showing the boundaries of the City of Annapolis Water System. For Fire Flow Tests in the City of Annapolis, call the City of Annapolis Fire Marshal’s Office at 410-260-2202.

If you are not sure which jurisdiction provides water to your location, send an email to providing the site address and state that you are interested in requesting a fire flow test. You will receive a response identifying the jurisdiction responsible for your water supply.

The county charges $232 per fire flow test. Payment must be made at the time the online application is submitted.

Online Application

Or, you may complete the Application Form and follow the directions on the form.

DPW provides the test results in tabular and graphical formats and distributes the test results via email to the applicant, the Fire Marshal, and the Permit Center. 

Test results will be available within 3 - 4 weeks from the date of application receipt. However, during the winter months, testing may be delayed due to inclement weather.


Utility Engineering