After you use the water in your home, it flows through the drain and into the wastewater (sanitary sewer) pipes to the wastewater treatment facility called the Plum Creek Water Reclamation Authority (PCWRA). Here, this wastewater is treated to environmental standards and is released into East Plum Creek.

Castle Rock Water maintains 280 miles of sewer lines and 10 lift stations that transport the wastewater from our homes and businesses to the treatment facility. For general maintenance and to prevent overflows, Castle Rock Water monitors inside these sewer lines and jet cleans them periodically. Castle Rock Water wastewater services also include identifying and replacing damaged and aging infrastructure.

Plum Creek Water Reclamation AuthorityPCWRA plant

The Plum Creek Water Reclamation Authority is an independent wastewater treatment facility that collects and treats the wastewater for five communities. It processes 6.44 million to 9.44 million gallons of wastewater every day. It is governed by a board of directors from three of the five communities it serves: Town of Castle Rock, Castle Pines Metropolitan District, and Castle Pines North Metropolitan District.

First treatment steps

At the wastewater treatment plant there are several processes designed to remove contaminants and disinfect the wastewater so that it meets State and Federal regulations.

  • The first step in wastewater treatment is to collect samples and measure the flow into the facility.
  • Larger non-biodegradable materials are then removed with mechanical screens.
  • The screened wastewater then flows into settling basins where heavier particles such as sand, gravel and eggshells settle to the bottom of the basins and are removed from the process

These first steps of treatment are important to protect the downstream processes and equipment in the facility.

Secondary treatment

Secondary treatment is the biological stage and involves microscopic organisms and bacteria that are responsible for the majority of the treatment process.

  • Wastewater is treated for 24 to 36 hours in large tanks where the bacteria consume various contaminants, specifically the biodegradable organics, ammonia, carbon and phosphorous.
  • Once treated, wastewater flows into large clarifying tanks where the bacteria and microorganisms settle to the bottom and are separated from the treated wastewater.
  • These bacteria and other organic residue is dewatered with centrifuges creating a usable bio-solid. These bio-solids are hauled away to be beneficially reused as fertilizers to improve soil conditions in crop and range land.
  • Treated wastewater from the clarifiers is filtered and disinfected using ultra-violet light to deactivate or kill any remaining pathogenic microorganisms.
  • The treated water is then measured, sampled and tested to ensure it meets or exceeds State and Federal requirements.
  • The final water (effluent)is then either released into Plum Creek or pumped to local golf courses to be used for irrigation.

To learn more and arrange tours of the facility, visit the PCWRA website.



The Plum Creek Water Reclamation Authority wastewater treatment facility services five residential-focused communities with very little industrial, agricultural or medical waste. Therefore, most of the pollutants are domestic, meaning they come from people. Many of these pollutants can be reduced by everyday actions. Reducing pollutants going into the system will reduce costs for treatment.

  • Don't use flushable wipes. While labeled as "flushable," these wipes do not disintegrate like toilet paper and often clog pipes, create sanitary sewer overflows and damage equipment at the wastewater plant.
  • Don't use the toilet as a trash can. Not only does this waste water, these items can create obstructions potentially causing sewer overflows and costly removal at the wastewater plant.
  • Don't flush medications. Dispose of expired or unused medications in the lobby of the Castle Rock Police Department. Advanced treatment options are needed to filter pharmaceuticals.
  • Don't wash fats, oil and grease (FOGs) down the drain. FOGs will line the pipes causing buildup in the collection systems, leading to sanitary sewer overflows. FOG is also difficult to remove at the wastewater plant. Scrape food scraps and FOGs into the trash where they can be properly disposed.
  • Choose phosphate-free detergents, soaps and household cleaners. Excessive phosphorous is expensive to treat for at the wastewater plant and creates algae blooms which negatively affect a natural ecosystem.


Contrary to popular belief, storm drains are not part of the wastewater (sanitary sewer) collection system. The many stormwater pipes in our streets and neighborhoods help manage potential flooding by taking rainwater and snow melt through detention ponds and channels, and then to the creek. Stormwater pipes and channels do not go to the wastewater treatment facility. Since these drains and channels go directly to the creek, it is critical to not dump anything down the storm drain.