Water Sources

Telluride's Water Sources

The Town of Telluride has three sources of water for treatment. Its two main water sources are Mill Creek and Blue Lake in the Bridal Veil Basin. These are year-round surface water supplies that are treated at the Mill Creek Water Treatment Plant and the Pandora Water Treatment Plant, respectively. Stillwell Portal supplies the Cornet Creek Water Treatment Plant as Telluride’s third water source. It is a ground water supply that typically provides Telluride with water from May to September. Stillwell is considered a backup water supply at this time.

Our Water Purification Processes

There are different requirements for treating ground and surface waters.

Pandora Water Treatment Plant – We collect water from various locations in the Bridal Veil Basin into pipes and send it directly to the Pandora Plant where we take advantage of the head created by water falling nearly 1,000 feet to generate power for sale to the local power cooperative—San Miguel Power Association. The water is then pumped from a stilling basin through a micro filtration process. After filtration, chlorine is added to satisfy state requirements for disinfection. The finished water then flows downstream to the Pandora water storage tank and on to the public.

Mill Creek Water Treatment Plant - We settle the raw water in a pond and then bring the water into the treatment plant, add a coagulant to help clump the dirt and slow stir the water in a process called flocculation. Here we add a small amount of chlorine to control algae growth and keep the membrane filters clean. The water is then run against settling tubes that deflect the larger clumps of dirt and settle it to the bottom of a clarifier. Next we pump the water through a micro screen to remove any larger objects (objects greater than 1micron) remaining that could hurt the membrane filters. The water is then forced through an Ultra filtration process which removes all particle larger than 0.01 microns. These filters are hollow tube fibers that provide a direct barrier to particles larger than 0.01 microns and produce water with a turbidity of about 0.04 Ntu, well below the state required 0.3 Ntu. (Nephalometric Turbidity Units, or Ntu, is a standard for how much dirt is in the water.) We add more chlorine to meet state requirements and send the water to storage tanks and on to the public.

Cornet Creek Water Treatment Plant – In the summer, when water is available from this source, we filter the raw water through a rapid sand and anthracite filter then take part of that flow and run it through a titanium oxide filter which adsorbs arsenic. We then blend Mill Creek and Stillwell water to produce a water with half the state required arsenic level or about five parts per billion. Then, we add chlorine to meet the required state levels for disinfection.

Ensuring a Quality Water Supply

We monitor continuously for finished turbidity and chlorine levels, test for E.coli in the distribution system nine times a month, test for total organic carbon (TOC) once a quarter, test for inorganics, fluoride, nitrates Total Tri Halo Methanes (TTHMs) and Halo Acidic Acids (HAAs) once a year, and test for synthetic and volatile organic compounds once every three years. Lead and copper testing is done once every three years and radiological testing every nine years. We do not add fluoride to our water. All results are presented in our annual Consumer Confidence Report.