Denver Plumbing: Licensing, Permits & Water

Colorado's State Plumbing Board licenses the plumbers; Denver's Community Planning and Development licenses the companies. The CPD contractor license is a true second gate: the application leads with the current state Plumbing Contractor card, runs on a two-year cycle, and is what actually entitles a firm to receive city permits. For a homeowner hiring help, that means two lookups instead of one.

• Authority. Colorado State Plumbing Board (DORA) statewide, plus the City and County of Denver's own contractor licensing through Community Planning and Development (CPD)
• Structure. Two layers: plumbers hold the state credential, and companies additionally hold a Denver CPD contractor license to receive city permits. The application requires the current State of Colorado Plumbing Contractor card up front, and the license runs two years
• Worth knowing. Checking a Denver plumbing company means checking both ledgers: the state board for the trade credential and the CPD contractor license that actually unlocks city permits.

Checked against the official source, September 2026: www.denvergov.org.

The homeowner permit is earned, not assumed: single-family only, legal owner and resident with photo ID matching the assessor's database, no trusts or LLCs, a year of occupancy owed after the work, and for plumbing, an exam passed first, with a state license accepted in its place. Once qualified, Denver is generous: a long list of ordinary jobs, from water heaters and softeners to floor drains, rides quick permits issued immediately without plan review, and a designated worker may lend hands under the city's written-approval rules on payment.

• Permit office. Community Planning and Development (CPD), Development Services, 201 W. Colfax Ave., with permits through the city's E-permits system
• Homeowner rule. Yes, with a Denver twist: homeowner permits issue only for a single-family home to the legal owner and resident (photo ID against the assessor's records; no trusts, LLCs or corporations), and for plumbing work the homeowner must first pass an exam, with a state license accepted as a substitute; the owner must then occupy the home for at least a year after the work.
• Process. A defined list of single-family plumbing jobs (water heaters, water service, showers, tubs, sinks, water closets, backflow preventers, floor drains, water softeners) qualifies for quick permits issued immediately without plan review, with inspections following; a designated worker may assist an owner-occupier but may not take payment without the Building Official's written approval.

Checked against the official source, September 2026: www.denvergov.org.

Denver Water's 2026 quality report puts system hardness at an average of about 105 mg/L in a 55-to-124 range: soft to moderately hard snowmelt, harder in winter and softer during runoff. The 105 mg/L shown above is that system average. Scale builds slowly here. The utility's larger project is lead: the Lead Reduction Program is replacing an estimated sixty thousand-plus customer-owned lead service lines with copper at no direct charge, targeting completion before 2035, with filters provided until each line clears. Construction itself moved to the 2025 Denver Building and Fire Code (2024 model codes with Denver amendments) in January 2026.

• Utility. Denver Water
• Supply source. Entirely mountain snowmelt from about 4,000 square miles of watersheds on both sides of the Continental Divide, crossing under it through the Moffat and Roberts tunnels
• Hardness. 105 mg/L (≈6.1 gpg), moderately hard; utility report, 2026

Utility information: www.denverwater.org. The hardness figure is the same record shown on the Colorado page.

• Drain Cleaning
• Water Heater Repair

  Water heaters and softeners ride Denver's quick permits, issued immediately with no plan review, and 105 mg/L snowmelt keeps scale slow.

• Sewer Line Repair
• Septic Tank Pumping
• Leak Detection & Repair

  Denver Water is replacing 60,000+ customer-owned lead service lines with copper at no direct charge, targeting completion before 2035.

• All services →

This page explains how plumbing is regulated in Denver; it is not a provider directory. For the job itself, describe the problem and your ZIP: a license-checked plumber who covers Denver gets the details and contacts you with next steps and a quote.