An Inside Look at Water and Fighting Fires

10/25/2017 | NANCY ZALUTSKY

An Inside Look at Water and Fighting Fires
Nancy Zalutsky

Nancy Zalutsky | Water Rights Specialist | Bio

This year, as is often the case, water is scarce at the time it is most needed because water suppresses wildfires with less impact than shovels, bulldozers or chemicals[1] . As I watched the choppers and planes carrying water and chemicals mixed with water to fires, I wondered how fire managers find, access, move and use water and how much water it takes to put out a forest fire.

Where do firefighters get water? How does it get to the fire?

Firefighters get water wherever they can: hydrants, tanks, tanker trucks, new or existing wells, lakes, springs, streams or even backyard swimming pools. During the 2015 drought in California, firefighters prepared for the fire season by practicing setting up and filling portable pools. That way, if sources near the fire were too low, crews could quickly assemble the pools to hold trucked-in water.

In order to get water to a fire, firefighters will move water to the fireline by truck, pump, gravity sock or backpack. Water has even been transported by mule train. Since water is heavy, weighing 8.34 pounds per gallon, conserving it is vital. Fortunately, a backpack of water can extinguish 300 times its volume of burning fuel if properly applied at the base of the flame, but ground crews need air support to be able to get to a spot where they can properly apply water.

I was surprised to learn that water bombers do not put out fires. Instead, they knock down hot spots, help prevent fires from spreading, and cool down the fire in an area so ground crews can work safely. Depending on the available water and equipment, large scooper planes can accumulate 1,600 gallons of water in 12 seconds.

In August 2017, the Boeing 747-400 SuperTanker was first used in the United States after it was activated to fight the Ponderosa Fire east of Oroville, CA . The aircraft can carry 19,000 gallons of water or retardant. A more familiar big air tanker is a three-engine DC-10 that can carry up to 11,600 gallons. The smaller and more agile helicopter have buckets that range in size from 45 to 2,600 gallons and can dip into smaller lakes and rivers. Land-based tankers load water or retardants at airport tanker bases.

How much water is used in wildland firefighting?

According to the National Interagency Fire Center in Boise, the amount of water used for wildland fire suppression is not tracked. Fire managers use different tools and strategies for different fires. The amount of water used on each fire varies by type of land, e.g. rangeland or timber, whether burning is beneficial or a threat to life and property and whether water can be maximized by additives that improve its efficiency.

Water with additives is used by ground or aerial application. Foam fire suppressants enhance water by reducing runoff, absorbing into fuels faster, keeping fuels cooler and protecting fuels from ignition. Once the water in the foam has evaporated, it is no longer effective. Gels improve the ability of water to cling to vertical and smooth surfaces by making water thick and sticky. The thick, sticky layer of water insulates fuels and delays ignition. As with foams, gels also rely on the water they contain to suppress the fire. Once the water has evaporated, they are no longer effective. Generally speaking, gels last longer than foams. Long-term retardants contain retardant salts (typically fertilizers) that alter the way the fire burns, decreasing the fire intensity and slowing the advance of the fire, even after the water in the mix has evaporated.

In addition to putting out fires, fire managers must get water to support fire camps that may be larger than many Montana towns. This includes primarily bottled water for drinking and water for catering, showers and sanitation. After the fire is contained and equipment is moved from one incident to the next, the National Wildfire Coordinating Group recommends washing down vehicles, personal gear, cargo nets, etc. to prevent the spread of noxious weeds. Fire resource managers also follow a strict protocol for decontamination of equipment to prevent the transmission of invasive aquatic species.

How much red tape is required to use water for firefighting?

As a water rights consultant, I have helped clients get through water rights adjudication and permitting, which can take years to complete. I was relieved to discover that fire resource managers only have to find water and use it. Montana law provides for temporary emergency appropriations without prior application for a permit if necessary to protect lives or property. M.C.A. ยง 85-2-113 (3). Although water may be used without prior approval, the use must cease immediately when the water is no longer required to meet the emergency. A.R.M. 36.12.105. However, fire managers may be prevented from using a nearby water source because it supplies drinking water or supports endangered species. Although no permit or limitation is placed on emergency appropriations, firefighters are encouraged to conserve water because it is heavy, may run out a critical time or must be replaced by pick and shovel work.

The Montana Legislature recently enacted a water permit exemption for local governmental fire agency using water only for emergency fire protection, emergency fire training, and emergency fire-related operations, which may include enclosed storage.

What about water quality?

Fire managers protect water quality because the fire suppression should not create more impact than the fire. Therefore, firefighters use water in place of chemicals in sensitive areas. Approved fire chemical products have been tested and meet specific minimum requirements regarding animal and aquatic toxicity. The Resources Advisor must report known accidents and spills in and near any body of water and develop a local plan for dealing with a spill. The National Wildfire Coordinating Group also sets guidelines for avoiding degrading water quality by camping and personal sanitation practices[2].

The Incident Management Team begins planning for demobilization on the day the incident starts. Demobilization includes restoring drainages by removing fill and dams, reestablishing crossings and returning the drainage to its natural configuration. Water bars may be used to prevent erosion, and wood sediment dams help prevent degradation of water sources.


Regardless of when, where and how firefighters get water to control and extinguish fires, it takes a lot of water, specialized skill and even some luck to end September that ended the fire season. Now post fire teams are taking action on federal lands to assess and protect burned watersheds because we will need them again to prevent and fight fires.