Almost every year, devastating wildfires burn in the western United States and Canadian forests. Even if you are far enough to not see the flames and smoke, swimming pools in the region may still be affected. Wildfire ash and soot can travel hundreds of miles.
Covered in this article:
- What do wildfires do to swimming pools?
- Ash, soot, and char: what's the difference?
- Airborne ash and soot travel far
- Ash and debris need to be cleaned out of pools
- Fire retardants and swimming pools
- Firefighting helicopters and water vessels
- Proactive pool chemistry against wildfire contamination
- Conclusion
What do wildfires do to swimming pools?
In short, wildfires contaminate swimming pools with high levels of carbon, nitrogen, and phosphate compounds. The severity of the contamination can vary widely based on winds, rainfall, and proximity to the fire.
A good rule of thumb is if you can smell the smoke, or notice the haze in the air, the fire is impacting swimming pools in the area too. These pollutants present a significant challenge for pool owners and operators in maintaining water quality.
Ash, soot, and char: what's the difference?
In researching for this article, we learned the differences between ash, soot, and char. We often use these three terms interchangeably, but they are chemically different.1 According to this source:
Sootis a fine carbonaceous material produced during incomplete combustion.
Charcomprises mostly carbonaceous, large, irregular fragments of burned material.
Ashis the decarbonized (mostly inorganic) residue of cellulose material. It typically comprises mineral salts, carbonates, oxides, or metal/noncombustible compounds.
We are unsure if the fine gray and brown dust that lands in pools near wildfires is soot or ash, but we do know that it complicates water chemistry. It could be a mixture of both. We do not know.
Airborne ash and smoke travel far
Wildfire (and for that matter, volcanic) ash and smoke can travel hundreds (if not thousands) of miles. Such smoke can cause flight delays and cancellations, as well as disrupt local weather patterns.
It's not uncommon for wildfire smoke to travel halfway across the continent, or even further. Wildfires are not just a California and Pacific Northwest issue. They happen in forests throughout the world. In 2023, Canadian wildfires created smoke that covered the Northeastern United States, including New York City:
The point we're making is that smoke and ash travel far, contaminating pools along the way. We had several calls from Northeast customers of ours struggling with algae and other issues amidst the smoke from the Canadian wildfires. That is to be expected, especially if you have nothing in your water capable of addressing carbon, nitrogen and phosphate compounds.
So let's say your swimming pool is in the smoke path of a wildfire. What can be done? What should be done?
Ash and other debris need to be cleaned out of pools
If you have physical ash and other wildfire debris in the pool, it needs to be physically removed as soon as possible. There are no shortcuts to this. Relying on the pool's filtration system and chemistry is not practical to address such concentrations of contaminants.
If you live in a wildfire-prone area, consider getting a mesh net with a better micron filtration rating. These enhanced nets are not optimal for normal netting of leaves and bugs, but will be better for removing fine particles like ash. The high levels of nitrogen and phosphorus make this debris excellent for gardening and lawn care, but not for pools.
Furthermore, wildfire ash has an alkaline pH above 9.0.1,2 This means it can rapidly increase the pH in the pool. It can potentially increase pH enough that whatever chlorine you had in the water breaks away from CYA and cannot be protected from sunlight degradation.
Related: Phosphate Removal (Pillar 3)
Filtering and vacuuming the pool will dramatically improve any chemical treatment you follow it up with. Again, we strongly advise against any shortcuts to actually cleaning the pool. We also suggest cleaning the deck around the pool, perhaps with a garden hose to clear debris off the deck that may otherwise find its way into the pool after you leave.
Fire retardants and swimming pools
Fire retardants dropped from helicopters are loaded with phosphates. If your pool looks like this, draining and refilling is probably the best option. Image Credit: AP - Kent Porter
Firefighting helicopters and water vessels
If you live in wildfire-prone areas like California, in many areas, swimming pool water is fair game for firefighting helicopters.
Image credit: Caters News Agency
The water vessels these helicopters tow are constantly flying over the worst of the wildfires. Ash, smoke, and whatever else is rising from the flames can be on the vessel that dips in your pool to capture water. Sure, there are enough pools in Southern California that yours is not likely to be drawn from. But if not, there’s a good chance that helicopter’s water vessel shared some ash and debris with your water.
Related Article: Smoke on the Water and Ash in the Pool - Robert W. Lowry, PCTI
Proactive pool chemistry against wildfire contamination
Since the primary contaminants are phosphorous, nitrogen and carbon compounds, we can build a proactive strategy before the fires burn. Orenda makes three products in particular that are excellent at managing wildfire contamination.
Assuming proper circulation and filtration, our CV-600 and CV-700 enzymes will help speed up the cleanup process by managing the non-living organics falling into the pool. Maintaining a residual of CV-600 before the fires is an excellent defense to manage hydrocarbons and other organic materials that get into the pool. Read more about CV-600 and CV-700 in our help center.
For removing phosphorus compounds, there's nothing like PR-10,000 Phosphate Remover Concentrate. Customers who use PR-10,000 already know its strength and high removal rate. Read more about PR-10,000 in our help center.
If you still have particles that you need help cleaning up after netting the debris out, you can try CE-Clarifier too. But nothing will replace physically cleaning the pool and filters. Read more about CE-Clarifier in our help center.
Conclusion
As wildfires become increasingly common and the winds continue to blow, it is crucial to acknowledge and address this ongoing reality. With wildfires expected to recur year after year, the accumulation of ash and debris in our pools presents a significant challenge, leading to chemical imbalances and strain on equipment. Understanding the impact of phosphates and nitrates on chlorine demand and efficiency, it is essential to be proactive in preparing for the influx of micronutrients that wildfires can introduce into our pools.
Good luck out there, and if the blaze is headed your way, don’t wait…be safe and evacuate.
1 Delia, A., Baxter, D. (retrieved in June, 2024). The ABC's of Wildfire Residue Contamination Testing.
2 Wandersee, M., Zimmerman, D., Kachurak, K., Gumapas, L.A., Wendt, K.D., Kesteloot, K. (2023). Wildland Fires Could Be Putting Your Drinking Water at Risk. Park Science Magazine. Vol. 37 (1).