The city of Sisters currently has enough water rights for the next 20 years, according to Public Works Director Paul Bertagna in his report to the joint workshop of the City Council and the Planning Commission on June 15.

Sisters’ water supply is 100 percent groundwater from wells drilled in 1975, 1992, 2007, and 2021.

Well No. 4 was drilled ahead of schedule because of the water rights gifted to the City by Dorro Sokol’s daughter, Cris Converse. The pump in well No. 4 sits at 160 feet, but the depth of the well was drilled to 300 feet, providing room to lower the pump if water levels decrease.

At this point in time, the recharge rate for Well No. 4 is seconds, rather than minutes or hours. The well was built to pump 1,500 gallons per minute. City-wide, with all four wells, the city can pump over nine cubic feet per second, or 4,000 gallons per minute.

The city sits on the edge of a large basalt aquifer rather than the shallower alluvial type. Because of being on the edge, the city can experience greater fluctuations in the water levels, but there is generally a delta of 25 feet. Climate cycles also can cause fluctuations. Prior to 1993, the city water level was decreasing. There was a heavy snow year in 1994 and an extra wet year in 1996, which put the delta back up to 25 feet.

The City began working on reducing water consumption several years ago and will continue that effort from here on out, according to Bertagna, who urges everyone to practice smarter water usage. In the past, demand has increased five to six times during the summer months.

The Water Master Plan is updated every five years. Reviews are done of peak water demands, population forecasts, storage for adequate fire flow, and other factors. Planning has been moved up for a new, larger reservoir and a replacement trunk line into town, because of the current and projected growth in population.

Because Sisters’ ground water is filtered through basalt rock, it doesn’t require any kind of treatment. A small amount of chlorine is added to maintain the safety of the delivery system.

System development charges (SDCs) paid by developers of new housing mean that growth is paying for growth. Improvements and additions to the water system necessitated by growth are paid for by those SDCs.