Fire Flow Standards

What is Fire Flow?

Fire flow is water required for firefighting purposes, usually a system of underground piping and fire hydrants. The International Fire Code, as adopted by Cowlitz County, requires fire flow to be provided for most residential and all commercial properties. Fire flow is often installed when building lots are created, but when required, will always need to be in place prior to construction of a building or use of the property. Fire flow usually consists of fire hydrants properly located on a public water line, but could also be smaller public or private water supplies or systems.

How much water is required?

Residential buildings up to 3,600 square feet usually require a minimum of 1,000 gallons per minute (GPM) for a minimum flow duration of 1 hour. Larger homes and commercial properties require additional fire flow based on the size and use of the site. When automatic sprinklers are installed, these requirements may be reduced. In addition, Cowlitz County has adopted a variety of options to assist homeowners and low hazard small businesses to meet fire flow requirements.

Methods of meeting fire flow requirements:

Cowlitz County Fire Code provides a variety of credits and reductions to fire flow water requirements. These include, but are not limited to, setbacks to property lines, proximity to a manned fire station, provision of defensible space, and ignition-resistant construction.

See our front counter for more information, as well as Cowlitz County Code Section 16.05.080.

Special circumstances:

At times, fire flow requirements may be increased or decreased by the Fire Marshal. Reasons to allow a decrease might be remote locations, or special construction considerations that decrease fire hazards. Situations that are deemed to increase or create special fire hazards may require an increase in required fire flow. Building size or use, construction materials, and location on property may contribute to a required increase.


Questions regarding the requirements for your specific project should be directed to the Building & Planning Department early in the development process. This will allow proper planning and help to avoid costly or timely delays for your project.

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