When You Need a Private Well
In Colorado, homes outside a municipal water service area must rely on a private well. About 20% of Coloradans use groundwater for home water.
Any new well (outside a "designated" groundwater basin) requires a permit under state law (CRS 37-90-137). Rural and semi-rural properties (or new subdivisions without piped service) typically drill wells.
Well Drilling Costs in Colorado
A complete private well system in Colorado typically costs $10,000–$50,000, depending on depth and geology.
Timeline: From Decision to Drinking Water
Expect 2–4 months from your first call to potable water. The Colorado DWR notes permit review may take up to 49 days for a complete application.
Permits & Process
Process Overview
- Site Evaluation: Confirm water rights/availability (double-check no available municipal water).
- Hire Licensed Contractor: Colorado requires a Board-licensed well driller and pump installer.
- Water Well Permit: Contractor or homeowner files a well permit application with the Colorado State Engineer (DWR). The first step is completing the correct form and paying fees (required by CRS 37-90-137).
- Permit Review: DWR processes applications in order; a complete residential application may require up to 49 days. You must post the permit at the well site during drilling.
- Notification of Start: Prior to drilling, the contractor must notify DWR's Well Inspection Program at least one day in advance.
- Drill the Well: Contractor drills per permit requirements and submits a Well Construction/Yield Report (GWS-31).
- Install Pump: After installation, a Pump Installation & Equipment Test Report (GWS-32) is submitted.
- Disinfection: The well is chlorinated/disinfected (owner can often do this with bleach).
- Water Quality Testing: After chlorination, water samples are taken. Bacteriological testing is typically required immediately.
- Inspection/Approval: Colorado does not send a state inspector to the site for private wells. Local authorities (county health or building) may require evidence of passing lab tests before occupancy.
- System Completion: Once tests pass, complete plumbing connections and enter water service.
Who Does What?
Driller Handles:
- Technical and permitting paperwork
- Well logs and reports (GWS-31, GWS-32)
- Drilling per permit conditions
- Initial disinfection
- Yield testing
Homeowner Handles:
- Securing the permit (signing water rights details)
- Ensuring water is safe to drink
- Coordinating lab testing
- Record keeping
- Compliance with permit conditions
Water Quality
Recommended Testing
- At Commissioning: Test new wells for total coliform and E. coli, nitrates, and area-specific contaminants (arsenic, fluoride, uranium, etc.).
- Ongoing: Test your well at least annually for bacteria (total coliform/E. coli) and do a comprehensive chem profile (including nitrate) every 2–3 years.
- Who Pays: Testing fees are paid by the homeowner (or buyer in a real estate transaction).
- Labs: Use CDPHE-certified drinking water labs.
Common Colorado Contaminants
Nitrates
Common on the Eastern Plains and irrigated valleys (from fertilizer, manure, septic). High nitrates (>10 mg/L) pose an infant health risk.
Arsenic
Found in parts of Western/SW Colorado and mining districts. Test new wells before use.
Radionuclides
Uranium/radium in some Front Range and Western Slope aquifers. Fluoride elevated in Four Corners area.
Iron/Manganese
Very common statewide – causes staining and metallic taste.
Hard Water
Nearly all CO wells are "hard" (dissolved calcium/magnesium). Water softeners are common solutions.
Treatment Options
- Disinfection (for bacteria): Shock-bleach the well (chlorination). Continuous chlorination or UV units if bacteria persist.
- Point-of-Use Filters: Under-sink or pitcher systems (charcoal or reverse-osmosis) for drinking water only.
- Point-of-Entry Systems: Whole-house units. For hardness, water softeners (ion exchange). For iron/manganese, oxidizing filters.
- Arsenic/Nitrates: Reverse osmosis, distillation or specialized anion-exchange filters are most effective (RO or distillation removes >90% of nitrates and arsenic).
Maintenance & Troubleshooting
Annual Maintenance Checklist
- Ensure wellhead and casing are intact (no cracks, no contaminants around top)
- Check pressure tank gauge (tank pre-charge ~2 psi below pump cut-in)
- Consider annual shock chlorination
- Change UV lamp annually if used
- Test water annually (bacteria/nitrate at minimum) and after any work on plumbing
Warning Signs
- Sudden loss of pressure or pump cycling on/off rapidly
- Strange smells (rotten egg = hydrogen sulfide), color (rusty/brown = iron), or taste (metallic)
- Sputtering faucets or constant running pump
- Muddy water after drilling rains
- Visible cracks in well casing, missing cap, or sediment in tank
Find a Licensed Driller
Colorado law requires Board-licensed well drillers and pump installers.
Search Licensed Drillers in Colorado
Find Drillers Near You →How to Verify a Driller
The Colorado Board of Examiners maintains a list of licensed contractors (quarterly updates). You must hire a contractor on that list.
- Ask for their Board license number
- Verify on DWR's "Licensed Contractor Lists"
- Get 2-3 written quotes
- Ask for references from recent jobs
Resources & Contacts
County Health Departments
Local health departments often assist private well owners. For example, the Northeast Colorado Health Department (Sterling area) provides free coliform testing and nitrate testing clinics. Check your county's public health website for well-water recommendations.
Certified Testing Laboratories
Water tests should be done at a CDPHE-certified drinking water lab.
Key Regulatory References
- CRS 37-90-137 – Well permit required for new wells
- DWR Well Permitting – Forms and instructions
- DWR eForms Portal – All required forms (GWS-31, GWS-32, etc.)
Frequently Asked Questions
Are You a Licensed Driller?
Check out our compliance reference for Colorado drilling regulations, forms, and requirements.
Colorado Driller Compliance Guide →