Loading... Please wait...

Help Me Connect

How To Connect To A Fire Hydrant

In most US areas, individuals who need temporary water may purchase permits to use hydrants. The permit will generally require a hydrant meter, a gate valve and sometimes a back-flow preventer.

Most fire hydrants have two 2.5 inch hose connection outlets with 7.5 threads per inch (TPI) and one 4.5 inch-pumper connection outlet with 4 threads per inch. National Hose (NH) or National Standard Thread (NST) is often referred to as “fire hose thread” as this is by far the most common thread in use today by fire departments.

Here is a list of major U.S. cities using NH / NST threaded fire hydrants - Click Here

Two Ways To Determine Hydrant Size

Individual should contact their local fire department, water services or public works to determine the specifications.

You may also count threads per inch (TPI) and/or measure the outside diameter of the male (ODM) outlet to help determine thread type.

Commonly Used U.S. Fire Hose Connection Threads
MaleNational Standard
 Size NH or NST
 Inside Diameter Male  Outside Diameter of Male  Threads Per Inch
 1 1/2"  1.990  9
 2"  2.515  8
 2 1/2"  3.068  7.5
 3"  3.623  6
 3 1/2"  4.243  6
 4"  5.010  4
 4 1/2"  5.760  4
 5"  6.260  4
 6" 7.025  4

 

How To Connect To A Standard 2 1/2" Hydrant With NH / NST Threads


Products Needed:

  • One fire hydrant wrench (SKU: 189 or K07)
  • One adapter 2 1/2" Female NH / NST to 1" Male NH / NST (SKU: Aluminum 37R251 or brass HA2510F)
  • 1" Single, double or rubber covered hose with NH / NST threads
  • 1" NH / NST nozzle (SKU: NZ021, CFB100NST, or ST1530-PV)

Products Needed:

  • One fire hydrant wrench (SKU: 189 or K07)
  • One adapter 2 1/2" Female NH / NST to 1 1/2" Male NH / NST (SKU: Aluminum 37R2515 or brass RHA2515F)
  • 1 1/2" Single, double or rubber covered hose with NH / NST threads (Aluminum couplings recommended)
  • 1 1/2" NH / NST nozzle (SKU: NZ011, CFB150NST, or S2510-PV)

Products Needed:

  • One fire hydrant wrench (SKU: 189 or K07)
  • 2 1/2" Single, double or rubber covered hose with NH / NST threads (Aluminum couplings recommended)
  • 2 1/2" NH / NST nozzle (SKU: HGCFB250NST, BN25F or S2510-PV)

Products Needed:

  • One fire hydrant wrench (SKU: 189 or K07)
  • Hydrant ball valve with 2 1/2" NH / NST female inlet by 2 1/2" NH / NST male oulet (SKU: HBV25)
  • 2 1/2" Single, double or rubber covered hose with NH / NST threads (Aluminum couplings recommended)
  • 2 1/2" NH / NST nozzle (SKU: HGCFB250NST, BN25F or S2510-PV2.5)