[2022 AR] MS4 Permittees

2022 Report

Regulated Stormwater MS4 Permittees

All municipalities with Municipal Separate Storm Sewer Systems (MS4s) permits from the Colorado Department of Public Health and Environment (CDPHE) in the watershed have adopted stormwater programs consistent with Regulation 72 for construction projects within their jurisdictions. Regulation 72 requirements are more stringent than MS4 Permit requirements in Regulation 61 Colorado Discharge Permit System Regulations.

In 2022, the MS4 permittees conducted 14,880 inspections of over 3,095 construction sites. In addition, the MS4 permittees required that construction site owners/operators install 69 new permanent control measures that are designed to reduce or eliminate pollutants in stormwater before it enters Cherry Creek or its tributaries.

Further information on each MS4’s program can be found in their annual reports in the links below.

Find out more about MS4 Permittees' programs


Public Education

In addition to regulating construction sites in the Cherry Creek Reservoir basin, MS4 permittees also have programs to educate the public, respond to and eliminate illicit discharges, and reduce or eliminate pollutants in stormwater from municipal operations. Examples of these efforts include:


Grass Swale

Above & Beyond

Compressor Map photo credit: Town of Castle Rock

Landscape Ordinance Limits Grass Lawns for New Residential and Commercial Properties in Castle Rock, Colorado

On October 18, 2022 Town Council approved an ordinance that prohibits grass lawns in front yards of new homes permitted for construction after Jan. 1. 2023 – instead requiring low-water ColoradoScapes. On average, 42% of residential water consumption in Castle Rock is used outdoors. With the high cost of infrastructure to keep up with outdoor watering demand, coupled with Colorado’s frequent droughts and changing weather patterns, the Town of Castle Rock is implementing an ordinance limiting high-water-use grass lawns. “Keeping up with demand during the summer requires a lot of infrastructure that we only use three or four months out of the year, and it’s very expensive to maintain and expensive for ratepayers,” said Castle Rock Water Director Mark Marlowe. “We’re always trying to reduce peak demands because of the stress on our infrastructure.” The backyards of new homes will be limited to no more than 500 square feet of irrigated grass lawn. The requirements do not apply to existing homes. The ordinance also adds requirements for new nonresidential landscapes. This includes eliminating non-functional grass lawns, or areas of grass turf where play or recreational activities cannot take place. The requirements apply to apartments, condominiums, townhomes, HOA common areas and commercial businesses permitted after Jan. 1, 2023. These changes are anticipated to reduce phosphorus in the watershed both with less water waste from irrigation and less application of fertilizers.

water conservation

photo credit: Town of Aurora

Water Conservation Ordinance Passes Unanimously in Aurora, Colorado

An ordinance that went into effect on September 30, 2022 and was unanimously approved by the Aurora City Council allows cool weather turf for new development only in active or programmed recreation areas, such as sport fields and organized social/cultural gatherings. It prohibits turf in common areas, medians, curbside landscape (“tree lawns”), and in most residential front yards while restricting it in backyards to allow for 45% coverage or 500 sq. ft., whichever is smaller. The ordinance permits turf in the front yard in alley-loaded developments that do not include substantial backyards. It also creates a path for transition zones to allow developments with site plans that are currently approved to better blend in appearance with the new areas that will be covered by the ordinance. Finally, the ordinance prohibits the use of cool-weather turf for the development of new golf courses and it restricts ornamental water features, such as exterior decorative fountains, waterfalls, basins and ponds. Warm weather turfs that use less than 15 inches of supplemental irrigation, such as buffalo grass, are permitted. Mayor Coffman noted that continual drought in the arid west and the impacts of climate change weighed heavily in his decision to sponsor this ordinance. “Colorado is in a crisis,” he said. “We need to take action to ensure that Aurora can continue to grow responsibly.”

Household Hazardous Waste Recyling

water conservation

2022 Stormwater Permits and Inspections for Construction and Post-Construction Development

* Please note, that many of the PWQ may be maintained by Local Agencies and not CDOT. Local Agency Federal Funded projects were reviewed by the locals and through the CDOT review process. The Local Agencies will report these three projects to CCBWQA. Post-active sites have concluded work and are being re-established
1 1 site is Post Active
2 8 sites are Post Active
3 This includes anytime that Douglas County (DC) issued a "Stop Work Order" and anytime that DC assessed re-inspection fees on a construction site in the Cherry Creek basin.
4 This includes 3 stop work orders for the Town of Castle Rock.
5 This is all of the pond data for the Town of Castle Rock. Not all ponds are for flood control, but we don’t have a way to separate them this includes, zero retrofitted facilities, 131 facilities inspected, and 25 facilities maintained.
6 This includes 1 facility retrofitted and 381 facilites maintained for the Town of Parker.
7 Reinspection fees issued.
8 SCMs with Final Acceptance after 2007.
9 Inspections of SEMSWA owned/operated SCMs.