Castle Rock, CO

Greywater pilot project aimed at cutting Castle Rock water use & costs

Mike McKibbin
Rick Schultz with the Town of Castle Rock explains a Greyter greywater pilot project that filters shower water for use in toilets.Town of Castle Rock, Colorado

By Mike McKibbin/NewsBreak Denver

[CASTLE ROCK, CO] When residents in about 30 homes under construction in Castle Rock take showers in their new homes, they’ll be saving water.

That’s because the homes in the Canyons South subdivision are in a pilot project that involves the Town of Castle Rock, Lennar Homes and Greyter Water Systems.

Each home has a greywater system that takes water from showers and baths, filters it to remove hair and soap and pipes it to toilets in the home.

The filtered water replaces the town’s drinking water normally flushed down toilets.

Castle Rock adopted a greywater ordinance in 2019 allowing such systems to be installed.

“We thought this made sense because there are few remaining options if people want to save in-house water usage,” said Mark Marlowe, director of Castle Rock Water.

“We wanted to be part of the town’s incentives program for water efficiency,” said John Bell, chief commercial officer for Greyter.

Each system costs around $5,000 and is added to the cost of the home. Greyter and the town believe residents will have lower water bills with the systems and recover the added cost.

20% cut in water use expected

Frank Walker, division president for Lennar Colorado, said the home builder wanted to help find possible solutions to Colorado’s water issues.

“One of Greyter’s reasons for doing what they do is ‘why flush good drinking water down the toilet?’,” he added. “That made sense to us.”

Greyter estimated their systems can reduce in-house water use by around 20%. Put another way, that means a family of four could see a 20,000 gallons-a-year reduction, Marlowe said.
A diagram shows how a Greyter greywater system works. A new Castle Rock subdivision is part of a greywater pilot project to save on water.Town of Castle Rock, Colorado

The town’s long-term water efficiency goal is to cut per capita in-house water use by 18-20% in the next few decades, Marlowe noted.

The project will be ongoing so the data collected can help the town make further water efficiency decisions or adjust the greywater code, he said.

“The more water efficient we can be, the better off we’ll be,” Marlowe said.

Castle Rock, Denver initial projects

Lennar and Greyter also partnered to install systems in new homes in Denver’s Central Park neighborhood. By the end of 2022, Lennar hopes to have finished installation in 54 new homes in the two developments.

Walker said Lennar had closed on the sale of several Central Park homes since 2020.

“We’ve had many positive comments from homeowners there,” Walker added. “I mentioned at the Castle Rock ribbon cutting that some people in Denver had taken their friends downstairs to show them the systems. Not many people do that when they show off a new home.”

Greyter systems will be added to 19 homes in Tucson, Ariz., soon, along with others in Florida, Bell said.

Builders can save, too

A 2013 Colorado law allowed local jurisdictions to adopt regulations for greywater use as an opt-in program.

“We’re delighted at how far Colorado has come with greywater in the last five years,” said Mark Sales, Greyter’s chief executive officer. “Colorado is now a leader in the field.”

Bell noted not many states allow the use of greywater, so the potential market is limited.

Colorado has what Bell called “some of the highest water connection fees in the country” and builders can offset that by including Greyter systems in their homes to help meet a community’s water efficiency requirements.

“That’s a big deal these days for developers in the state,” he added.

The Castle Rock pilot project spurred the Douglas County Commissioners to direct the development of regulations to allow similar greywater pilot projects in new homes built within unincorporated portions of the Castle Rock Water and Sanitation District.

“Let’s get out of the way, do a pilot program and see where it goes,” Commissioner George Teal said during an April 25 work session.

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Mike McKibbin is an independent journalist on Colorado's Front Range and covers Douglas County for NewsBreak.

Denver, CO

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