Greywater in Colorado:
Permits, Denver's Process & Legal Installation

Colorado's Greywater Legalization: What Changed in 2013

Before 2013, greywater reuse was effectively illegal in Colorado under the state's prior appropriation water law doctrine, which treated all water — including wastewater leaving your home — as belonging to downstream water rights holders. HB13-1044 (signed by Governor Hickenlooper in May 2013) created a framework that allows residential and commercial greywater reuse, but with a key distinction from states like Arizona and Texas: Colorado requires permits for all residential greywater systems through the local government, with state oversight through CDPHE Regulation 86.

The practical effect is that you cannot install a greywater system in Colorado without going through your local authority — whether that's Denver Water, your city's public works department, or your county health department. The good news is that most jurisdictions have made the process straightforward since 2013, and Colorado's water scarcity reality (particularly on the Front Range) means officials are generally supportive rather than obstructive.

Colorado's Three-Tier Greywater Framework

CDPHE Regulation 86 establishes three tiers of residential greywater use, each with different permit requirements:

For residential homeowners, Tier 1 is the most common and practical. Tier 2 is available but adds complexity. Tier 3 is primarily for commercial or institutional buildings.

Denver: How to Get a Greywater Permit

Denver's process for residential greywater permits is handled through the Denver Department of Public Health and Environment (DDPHE) and is one of the most streamlined in the state. Here is the actual step-by-step process as of 2025:

1. Complete the Denver Greywater Permit Application — available at denvergov.org/environment. The form is a single page for Tier 1 systems. You'll need your address, a description of the water source (laundry), the approximate daily volume (estimate based on loads per week × gallons per load), and a sketch of where the discharge points are on your property.
2. Submit to DDPHE — by email, online portal, or mail. No in-person visit required for most residential applications.
3. Permit fee: Denver charges $50 for a residential Tier 1 permit (as of 2025). Verify current fees at time of application.
4. Review period: Most residential Tier 1 applications are approved within 2–3 weeks. Complex Tier 2 applications may take 4–6 weeks.
5. Inspection: Denver requires a post-installation inspection for Tier 1 systems. An inspector verifies the diverter valve, overflow connection, and mulch basin setup. Inspections are typically scheduled within 1–2 weeks of permit approval.
6. Approval: Once inspected and approved, your permit is on file with DDPHE. There is no recurring annual permit — it's a one-time approval.

Fort Collins, Boulder, and Other Front Range Cities

Fort Collins

Fort Collins Utilities operates a greywater pilot program that allows select residential participants to install greywater systems with city support. Applications to the pilot program (when open) are accepted through Fort Collins Utilities' conservation team. Outside the formal pilot program, Fort Collins homeowners can apply for standard greywater permits under the city's water ordinances — contact Fort Collins Utilities at fcgov.com for current application procedures.

Boulder

The City of Boulder has one of the more supportive environments for greywater installation. Boulder's Utilities division can issue permits for Tier 1 L2L systems through a streamlined process. Boulder also has an active Utilities rebate program — check boulderwaterwise.com for current rebate amounts. Boulder's permit process aligns closely with Denver's, with a similar application form and comparable fees.

Loveland, Longmont, and Smaller Front Range Cities

Most smaller Front Range cities defer to their county's interpretation of CDPHE Regulation 86. Larimer County and Boulder County both have their own permit processes for unincorporated areas. Contact your city's public works or utilities department first — if they don't handle greywater permits directly, they'll refer you to the county health department.

Rural Colorado and Mountain Communities

In rural Colorado, greywater permits are typically handled by county public health departments. The process is less standardized than in Front Range cities, and some smaller counties have less experience with residential greywater applications. A few practical notes:

• Many rural Colorado properties have septic systems rather than municipal sewer. CDPHE Regulation 86 requires that your greywater system's overflow connect to your septic — verify with your septic installer that adding overflow capacity won't overload your system.
• Mountain communities with shallow groundwater or rocky soils may face percolation challenges. In these areas, larger mulch basins with more surface area are preferred over deep basins.
• Some mountain counties with strict environmental overlay (protecting headwaters) have additional setback requirements beyond the state standard. Verify with your county health department.
• The Colorado Division of Water Resources (CDWR) may have additional interests in greywater reuse in areas with significant downstream water rights claims. This is more of an issue for large systems — residential L2L systems are generally not affected.

What Colorado Allows (and Doesn't)

Under Colorado's greywater framework:

Allowed under Tier 1 (L2L):

• Laundry water to outdoor landscape irrigation
• Drip, bubbler, or mulch basin application only (no sprinklers)
• Irrigation of ornamental plants, lawns, trees, and shrubs

Not allowed under Tier 1:

• Irrigation of edible food crops (root vegetables, leafy greens, strawberries)
• Surface ponding or runoff
• Spray application
• Storage longer than 24 hours (Tier 2 requires additional treatment)
• Use for toilet flushing (requires separate permit tier)

Frequently Asked Questions — Colorado Greywater

• Why does Colorado require permits when Texas and Arizona don't?+

  Colorado's prior appropriation doctrine ("first in time, first in right") historically treated even household wastewater as part of the water that downstream rights holders rely on. When you send greywater to your landscape instead of the sewer or stream, it's technically diverting water from the downstream system. The 2013 law created the permit framework as a compromise — local governments sign off that the volume is small enough not to harm downstream rights. Most residential L2L systems are well under any threshold that would affect water rights, but the permit requirement remains as a legal formality.

• How long does a Colorado greywater permit last?+

  Colorado greywater permits are issued for the life of the installation — there's no annual renewal requirement. However, if you significantly modify the system (add new zones, change sources from Tier 1 to Tier 2), you'll need to apply for an amended permit. If you sell the home, the permit transfers to the new owner and you must disclose the system's existence in the real estate transaction.

• Can I install greywater myself in Colorado, or do I need a licensed plumber?+

  A Tier 1 L2L system — which doesn't modify any existing plumbing — can typically be installed by the homeowner in Colorado. The permit application doesn't require a licensed contractor to sign off on Tier 1. For Tier 2 systems that involve cutting into drain lines, most Colorado jurisdictions require a licensed plumber to pull the permit and perform the plumbing work, though homeowners can often assist with the landscape portion. Check with your specific jurisdiction — Denver, for example, allows owner-builders to do the work if they pull the permit themselves.

• Is there a rebate for greywater in Colorado?+

  Colorado does not have a statewide rebate program. Some individual water providers offer rebates — Denver Water, Boulder County, and Fort Collins Utilities have all had rebate programs at various points. Check directly with your water utility for current offerings. Several Colorado water utilities also participate in the EPA WaterSense rebate database, which lists current rebate programs by state.