Fire Hydrant Geolocation

An easy to use, reproducible method to ID hydrants


You are tasked with testing or inspecting hydrants as a firefighter, utility worker, municipal employee and you are not really sure which hydrant you are standing in front of based upon the paperwork, PDA, tablet or laptop display. The hydrant’s tag or stencilled number is either missing or illegible and there is enough confusion in the description of location to not be sure. Does this ever apply to you?

If so, then using the following information, you will be able use your smart phone to uniquely ID hydrants forever with just 8 digits.

iPhone application MilGPS showing hydrant geolocation of 1999 5561

The recommended method is to utilize US National Grid (USNG) at 10 meter precision**, which is (8) digits. USNG is the national standard coordinate system for the USA. It does not use degrees, decimals, minutes, dashes, seconds; it is just letters and numbers. It is also the land search & rescue coordinate system since 2011; thus it is designed for land and is perfect to use now even as practice for use during an incident.


Full, worldwide coordinate is 17R NM 1999 5561 near Titusville, FL

1999 5561 has inherent meaning. It is the easting and northing component of a USNG coordinate. In words, it means that the location is 99% east and 61% north in 1 kilometer (Km) grid 19 55.

Do you need to know all that to use it to spot hydrants? No. What is good to know is the that the (8) digits are specific to 100 Km square ‘NM’. Realize that 1999 5561 is repeated 100 Km away, but not in your jurisdiction, in all likelihood. Therefore, 1999 5561 is unique and can be found easily in the future. Further, it represents an area on the ground that is 10 meters (33 feet) square. How many hydrants will be inside of a 33' square box? Typically only (1). By the way, this concept could be applied in pre-planning operations for geolocation of utility shut-offs, fire alarm panels, fire risers, hazmat, etc.

To find free or inexpensive applications that will display USNG, search for ‘MGRS’ in your app store. Note that MGRS is Military Grid Reference System, in use worldwide since 1949.

If you desired to take a picture of the hydrant to document some problem, it can be done with apps Theodolite, GeoCam or Recon Camera.

Take a picture with coordinates on the photo. Note that 1 meter precision is displayed in this app (Theodolite)

Finally, if you desired, you can plot the location of each hydrant or create a link to it for use in an email on a free web tool.

See this link: Hydrant 1999 5561

The example free web tool is Mission Manager. Optional accounts are free. Inside of an account a user can optionally mark hydrants, fire risers and numerous other items with icons and labels.

Hydrant 1999 5561 visible inside of 10 meter grid of same designation per screen shot of Mission Manager

Summary: Using free or low cost apps and web tools, fire hydrants can be uniquely geospatially identified in addition to whatever ID system is presently in use. The extra time taken to spot hydrants with USNG is minimal. The value-added may be large in the future. USNG is the language of location. Check it out.


For more information see the USNG Information Center or send email to: USNG08 @ gmail (dot) com


** Typical hand-held GPS devices are not accurate to 1 meter. Thus, display of 1 meter precision is beyond the accuracy of the device. Use of 10 meter precision is standard for fire-rescue operations for individual items. It is also easy to say or copy over the phone or radio due to being even rather that odd number of digits