What to Do After Wildfires

No words can adequately express the condolences felt for those who have suffered loss during the recent wildfires in California and the Northwest United States. In the case of active fires, the utmost concern should always be for the immediate safety of people and property first. The devastation of wildfires this year has been particularly extreme. The following is some advice for pool professionals dealing with the restoration and repair of swimming pools after a wildfire.

During the Fire

Water pressure and water quality at the source will be affected during and after times of wildfires. For residents trying to protect their property, using the hose may not always be effective. In some cases where water pressure becomes an issue during the fire, some fire departments may incorporate pumps in the pool to use the water for protecting homes. Homeowners in wildfire areas can also buy pumps that can soak down their property. These pumps can typically work at a flow of 150 gpm and can disperse the contents of a 20,000-gallon pool within two hours. Pool techs should be aware ahead of time of this possibility and should check that hydrostatic relief valves are in place on these pools to prevent the pool vessels from popping out of the ground during these emergency use times. If there is a high groundwater table or the pool is built over an underground spring, this could be a very real possibility.


All types of debris are possible during times of wildfires as result of potential high winds. Smoke, ash, tree branches, leaves and fire suppressant chemicals will all most likely end up in the pool.

There is the possibility that live animals may seek shelter in the water or pool area. Do not attempt to deal with live wild animals on your own. Immediately contact your local animal control or wildlife management officials.

Use extreme caution in and around areas where wildfires are still active. Protective gear such as respiratory mask, goggles and gloves may be required in these situations. It is prudent to carry some emergency supplies at all times. This could include bottled water, safety flares, a protective non-flammable blanket, a battery-powered radio and flashlight. In addition, it is vital to comply with the emergency management in the area. Avoid areas of heavy smoke where emergency crews are setup.

Service companies should never attempt to cross an emergency barrier or evacuation zone to deal with pools. Fire can change course and move rapidly especially in areas of high winds. If your route is anywhere near where fires are, make sure to have several planned escape routes thought out ahead of time. Smoke and ash can be a problem for miles beyond the fire. In the summer of 2017, smoke from the fires in British Columbia spread all the way down to the Seattle area. The airborne ash and debris affected many pools in the area. Some of the pools developed filter problems and bouts of algae.

After the Fire

Great care should be taken when undertaking the task of cleanup after a fire. Be aware of live downed power lines. In many cases in fire-damaged properties, the fire department will turn off the power. This is done because wires may have melted or been fused from the heat. Be sure to check with the fire department before attempting to turn pump and filter breakers back on. Only a licensed electrical contractor should determine the integrity of the breakers for the pumps.

Swimming pools in fire areas will contain ash, debris, firefighting chemicals and toxins. It is best when allowable to drain and refill the pool. Inspect the integrity of the pool walls, plaster, pipe fittings, decking and surrounding landscape. The components of smoke from fire can cause severe lasting damage to equipment and structures. In addition, the chemistry of the pool will be adversely effected. Smoke is corrosive and oxidative. It will cause severe damage wherever it has settled. If equipment and decking are covered in ash and smoke, continue to use caution. Wear personal protective equipment and a breathing apparatus as well as gloves. There are many toxins in smoke and ash residue that can cause sickness. The best case is to allow professionals to deal with excessive clean up situations.

The Contents of Ash

In the case of wildfires, there will be a lot of ash that ends up in pools. Ash from fires that burn lower than 840 degrees Fahrenheit is mostly organic carbon. At a higher temperature, the carbon is burned away and inorganic compounds are left. These include things like calcium, magnesium and sodium. The fires California not only burned forest, but also homes and structures. Because the combustion rate is much higher for buildings, the makeup of the ash is different. At a very high combustion rate, the ash can contain potassium and calcium oxides which create quicklime. If enough of this ash gets into the pool and then to the filter, it can create a limestone cement coating on the filter media. Ash from homes and structures can also contain toxins such as lead, arsenic and hexavalent chromium. Most of the ash that lands in pool water is also hydrophobic and repels water. This explains why the ash floats and is so difficult to remove by skimming. Changing the charge of the ash by using a chitosan clarifier or an enzyme can help in the removal of the ash.

The Ingredients of Fire-Fighting Suppressants

Most of the dry suppressants dropped on wildfires are a made primarily of di-ammonium phosphate. The result of this is an increase in ortho-phosphate ending up in the waterways and in swimming pools. Phosphate in pools leads to many water quality issues and can combine with calcium to form calcium phosphate scale on heat exchangers. In 2003, the Cedar Fire in San Diego was one of the biggest wildfires in California history. After that fire, pool service professionals reported a very high spike in phosphate levels in pools. This could have been in direct relation to the large amounts of phosphate-based suppressants that were dropped in the area.

In cases where homes were not damaged but were in a vicinity to the fire, the following steps can be taken:

  • Remove all larger debris as soon as is possible.
  • Brush all surfaces thoroughly.
  • Skim smaller material with a pool net.
  • Make sure filter is clean and in operational order.
  • Inspect all equipment.
  • Super-chlorinate the pool to 20 ppm or use a quality chlorine-free oxidizer.
  • Follow immediately with a clarifier to help remove small ash material to the filter.
  • Use of an enzyme can help break down some un-filterable non-living organic material.
  • Test and treat for phosphates once the chlorine levels have come down below 5 ppm.
  • Add a good broad-spectrum algaecide.
  • Clean filter as necessary throughout this process.

Further Cautions

The extreme heat from fires can cause the ground to bake, leading to a lack of absorption. The heat bakes the soil forming a solid layer that causes it to repel water. This is a condition known as hydrophobicity. When rains come, the hydrophobic condition of the soil increases the rate of water runoff. Water can concentrate in these areas, causing erosion. Excessive erosion can come from firefighting efforts and lead to flooding during rains. Pool areas need protection with sandbags or other diversion methods to drains to prevent an influx of floodwater in the pool.

Pools drained during the fire will need to be inspected for damage to plaster surfaces, deck areas and all equipment connections. Most likely, these pools will need to be re-surfaced before regular use can begin.

In conclusion:

  • Use extreme caution in areas where wildfires are active.
  • Always check ahead of time with emergency management personnel before attempting to enter neighborhoods where fires have been.
  • Wear smoke protection when necessary (breathing mask and goggles).
  • Water in pools can contain toxins from smoke and ash and firefighting chemicals it is best to drain when possible. No one should ever swim in a pool in the immediate aftermath of a fire.
  • Remember that wildfires can move fast and change course in seconds. Have more than one escape route planned ahead of time. It is best to stay out of the area.
  • Shock, floc, enzyme, phosphate removal and algae prevention are all good remedial treatments once the fires are gone.
  • Check and inspect all equipment thoroughly during the cleanup process. Filters may need to be backwashed and cleaned frequently during this time.
  • Ensure that pools equipped with firehose pumps also have hydrostatic relief valves to prevent popping from rapid draining.
  • Be aware of erosion and flooding problems that may occur from damaged soil. Sand bag any vulnerable areas in advance. Ensure that the flow of water is to drains and culverts to prevent flooding.



Terry Arko has more than 30 years of experience in the pool and spa/hot tub industry, working in service, repair, retail sales, chemical manufacturing, customer service, sales and product development. A Certified Pool Operator (CPO) and CPO Instructor through the National Swimming Pool Foundation (NSPF), Arko is currently a water specialist for NC Brands, parent company of SeaKlear and Natural Chemistry, which is a manufacturer of pool and spa products. For more information, visit www.ncbrands.com.