A wildfire is burning near Portland’s primary source of water in the Bull Run Watershed. Here’s what we know about the Camp Creek Fire.

Lightning sparked the blaze burning northeast of Sandy in the Mount Hood National Forest on Thursday, Aug. 24. As of late Monday morning, Aug. 28, it was 0% contained and had grown to about 1,600 acres in size, though crews said somewhat favorable conditions over the weekend had slowed its progression.

Is Portland’s water safe?

Yesterday afternoon, the Portland Water Bureau said the fire had crept closer to the city’s leading water source, burning approx. 1.3 miles from Reservoir 1 and 2.1 miles from the Headworks treatment facility on the western side of Reservoir 2. Officials said the body of water serves as a “natural buffer” between the treatment plant and the fire burning to the east.

Despite its close proximity, the bureau said Portland’s water was still safe to drink. Officials said the fire was mostly moving away from Headworks and the site’s water supply infrastructure is “highly defensible.”

How does a fire impact water quality?

Fire retardant used by crews to suppress flames in the Bull Run Watershed is made of 85% water, 10% fertilizer, and 5% “minor ingredients.” The Multnomah County Health Department said these ingredients pose a negligible risk to public health and, if they entered the reservoirs, would be diluted by billions of gallons of water (the same applies to falling ash). Retardants will not be used in areas that drain into the reservoirs.

Chlorine and diesel fuel for a backup generator are stored at the facility. In the event of a full evacuation, chlorine cylinders would be sealed and other flammable chemicals would be safe in fire-resistant containers.

Find the latest information about the Camp Creek Fire on InciWeb; follow the Portland Water Bureau’s fire-related updates here.