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Supporting fire protection

Each year, to support fire protection, Utilities Kingston inspects and flow rates the fire hydrants in Kingston’s water distribution system. Licensed water distribution operators inspect mechanical parts for proper operation, assess the overall condition, and flush and flow rate hydrants.

Operators flow rate a fire hydrant

Operators flow rate a fire hydrant

Operators flow rate a fire hydrant

Did you know? Treated water is de-chlorinated before it is discharged from the hydrant to Lake Ontario (our drinking water source).

Effect on tap water: discolouration and reduced pressure

Flow rating, as with other activities on the water distribution system, can disturb deposits that normally occur in water pipes. If you notice your tap water is brown or discoloured, please be assured the water is still safe.

Flush your pipes until the water is clear again.

  1. Locate the cold water tap that is closest to your water meter.
  2. Run the cold water until it is clear. This may take 5 – 25 minutes.
  3. If the water does not clear, please contact Utilities Kingston at 613-546-1181.

You may also notice temporary reduced water pressure while hydrant flow rating takes place. Once the operators have completed their work (this usually takes about an hour), water pressure will return to normal.

Colour coding

Fire fighters use colour coding to anticipate the water supply available through a hydrant when they arrive at the scene of a fire. Ensuring the water supply is trustworthy helps them save lives and protect homes and businesses from fire damage. Thus hydrants are colour-coded to indicate how much flow is available through a hydrant at that point in the water distribution system.

Fire hydrant classifications

Class Colour code Rated flow US gal/min @ 20psi L/s @ 70kPa
AA+ * Blue Greater than 2999 Greater than 189
AA Blue Greater than 1499 Greater than 95
A Green 1000 to 1499 63 to 95
B Orange 500 to 999 32 to 63
C Red Less than 500 Less than 32

* AA+ is a non-standard classification that assists the fire department in identifying hydrants and mains that are capable of providing higher flow rates.

Did you know?

  • There are 3,600 hydrants in the municipal water distribution system, which are proudly maintained and operated by the employees of Utilities Kingston.
  • Automated field data collection for the fire hydrant inspection program using the location-based application Collector for ArcGIS reduces paperwork and increases productivity by digitizing processes.
  • Fire hydrants in a municipal system are painted yellow to make them more visible at night.
  • Fire hydrants in a private system are painted red.
  • Utilities Kingston protects rebuilt fire hydrants with a Vortex coating system. This coating is highly resistant to impact, fading and K9P.
  • In addition to colour coding the bonnets and caps, we add coloured hydrant markers (in the shape of discs). The markers reflect at night and help fire fighters locate hydrants.

What's happening in 2022

All 3,600 hydrants in the municipal water distribution system are inspected each year and 20 per cent of the hydrants are flow-rated on an annual basis  This year, our goal includes hydrants in Zone Two and Seven, as shown in our map of hydrant zones. This target may change, as we continue to work within provincially-regulated COVID-19 restrictions.  

As part of this program, licensed water distribution operators from Utilities Kingston will inspect mechanical parts for proper operation, assess the overall condition of fire hydrants, and flush and flow-rate hydrants. Once the hydrants are rated, they are marked blue, green, orange or red to let firefighters know the flow rate (in US gallons per minute) of the hydrant.

We expect to complete flow rating from May to October, while inspection will continue into September. If you have any questions or concerns about this program, please contact customer service at 613-546-0000 or