Basics: Private Well vs. Municipal Water
Montana law requires a water supply for any new home. If public water is not available, a private well is needed. If municipal lines reach your property, connection is often required.
No Municipal Service
If municipal water lines don't reach your property (common in rural Montana):
- You must install a private well
- Most rural Montana homes rely on wells
- Septic system also required
Municipal Service Available
If public water lines reach your lot:
- Connection typically required by local ordinance
- Usually cheaper than drilling if lines are nearby
- Example: West Yellowstone requires connection
Subdivision Requirements
Small subdivisions (<20 acres) must obtain a Certificate of Subdivision Approval (COSA) from DEQ that specifies the water source (well, cistern, or public). County environmental health offices handle COSAs.
Well Drilling Costs in Montana
A complete private well system in Montana typically costs $10,000–$30,000, depending on depth, geology, and casing material.
Cost Tip
Get quotes from 2-3 licensed drillers. Costs vary by region and geology. Steel casing costs roughly twice as much as PVC but is required for deeper wells and certain conditions.
Timeline: From Decision to Drinking Water
Expect 2–6 weeks from your first call to potable water. Drilling itself takes only 1-4 days for most domestic wells.
Water-Right Permit Delays
If you need a water-right permit (wells >35 gpm), add 2–6 months to the timeline. Most domestic wells are exempt and only require Form 602 filing after drilling.
Permits & Process
Do You Need a Permit?
Exempt Wells (Most Domestic)
≤35 gallons per minute AND ≤10 acre-feet/year
- No pre-drilling permit required
- File Form 602 within 60 days after first use
- Filing fee: $250
- Secures your groundwater certificate
Permit Required
>35 gpm OR >10 acre-feet/year
- File Form 600 (Beneficial Water Use Permit) before drilling
- Processing time: 2–6 months
- Public notice process
- Required for large irrigation, commercial wells
Step-by-Step Process
- Contact a Licensed Drilling Contractor. Montana requires licensed drillers for all wells.
- Site Selection. Mark well location (avoid septic, property lines).
- Check Water Rights. Determine if Form 600 permit needed (if >35 gpm) or just Form 602 (if exempt).
- Drilling the Well. Licensed driller drills, installs casing, develops well per state standards.
- Pump Installation. Set submersible pump, connect wiring, disinfect well.
- Water Testing. Collect samples and send to certified lab.
- File Reports:
- Driller files Well Log (Form 603) to MBMG within 60 days
- Owner files Form 602 to DNRC within 60 days after first use
Who Does What?
Driller Handles:
- State licensing (DNRC BWWC)
- Drilling, casing, grouting
- Well construction standards
- Well log report (Form 603) to MBMG
Homeowner Handles:
- Water-right paperwork (Form 602 or 600)
- Paying fees ($250 for Form 602)
- Water testing (homeowner expense)
- Any local permits (COSA, building)
No State Well Drilling Permit
Montana does not require a separate "well drilling permit" from the state for exempt wells. However, subdivision approval (COSA) from DEQ is needed for new lots <20 acres, issued by local health authorities.
Water Quality
Important
Montana does not mandate water testing for private wells, but it is strongly recommended. Many dangerous contaminants are invisible, tasteless, and odorless.
Recommended Testing Schedule
- Annually: Total coliform bacteria, nitrate (EPA also recommends TDS and pH)
- At Well Install: Full suite (hardness, iron, manganese, arsenic, metals, TDS, pH)
- Every 3–5 years: Repeat multi-parameter panel
- After any event: Illness, flooding, plumbing changes, taste/odor changes
Common Montana Water Quality Issues
Bacteria
About 25% of Montana wells have total coliform; ~3% have E. coli. Indicates surface intrusion. Requires disinfection.
Nitrate
~3% of Montana wells exceed 10 mg/L limit. From livestock/fertilizer. Concern for infants and pregnant women.
Arsenic
~10% of wells exceed health standards. Natural from deep bedrock. Carcinogenic long-term. Test at install.
Manganese
~10% of wells above health standards. Causes staining and neurological concerns. Natural geologic source.
Iron & Hardness
Very common. Iron causes reddish staining. Hardness (calcium/magnesium) causes scale. Water softeners are common solutions.
Regional Hotspots
- Arsenic: Higher in southwestern Montana, Madison/Missouri systems, north-central ranges
- Nitrate: Irrigated valleys (Flathead, Missoula, Yellowstone Valley, Judith Basin), eastern plains
- Interactive maps: MSU Well Educated Water Quality Atlas
Arsenic Alert
If your property is in southwestern Montana, Madison/Missouri basins, or north-central ranges, test for arsenic before using well water for drinking. Long-term exposure is carcinogenic.
Treatment Options
| Issue | Treatment |
|---|---|
| Bacteria/E. coli | Shock chlorination, UV lamp, continuous chlorinator |
| Nitrate | Reverse osmosis, distillation (point-of-use) |
| Arsenic | Reverse osmosis, iron-oxide adsorption filters |
| Iron/Manganese | Oxidizing filters (greensand/Birm), chlorination |
| Hardness | Water softener (ion-exchange with salt) |
Maintenance & Troubleshooting
Annual Maintenance Checklist
- Test water for coliform and nitrate annually
- Ensure wellhead has sanitary cap (screened vent)
- Check pressure tank air charge (30-50 psi typical)
- Grade soil away from wellhead (no puddles)
- Keep hazards 100-250 ft away (fertilizer, fuel tanks)
- Check pressure gauge monthly (40-60 psi typical)
Warning Signs of Well Problems
- Loss of pressure/flow: Check tank switch and pump fuses first
- Pump runs continuously: Leak in line or waterlogged pressure tank
- No water: Check electrical; if working, well may be dry
- Cloudy/milky water: Air in lines or sediment entering well
- Rusty/colored water: High iron/manganese or corroded plumbing
- Foul odor/taste: Bacteria (hydrogen sulfide) or high sulfate – disinfect and test
DIY vs. Professional Help
You Can Handle:
- Water testing (collecting samples)
- Filter cartridge changes
- Shock chlorination
- Basic plumbing under sinks
- Clean surroundings
Call a Professional For:
- Drilling or deepening well
- Pump/tank replacement or repairs
- Electrical wiring to pump (licensed electrician)
- Major leaks or unclear problems
- Treatment system installation
Find a Licensed Driller
Montana law requires a licensed water well driller for all well work.
Search Licensed Drillers in Montana
Find Drillers Near You →How to Verify a Driller
- Contact DNRC Board of Water Well Contractors: 406-444-3111
- Ask for driller's license number and verify status
- Get 2-3 written quotes
- Ask for references from recent jobs
- Ensure driller provides signed well log (Form 603)
Montana Water Well Drillers Association
The MWWDA has a "Find a Contractor" tool and regional contacts.
Resources & Contacts
DNRC Regional Water Offices
- Billings – 406-247-4415
- Bozeman – 406-586-3136
- Glasgow – 406-228-2561
- Havre – 406-265-5516
- Helena – 406-444-6999
- Kalispell – 406-752-2288
- Lewistown – 406-538-7459
- Missoula – 406-721-4284
Certified Testing Laboratories
- Mission Mountain Laboratories (Arlee) – 406-745-5227
- Energy Laboratories (Billings) – 406-252-6325
- Bridger Analytical Lab (Bozeman) – 406-582-0822
Key Forms & Documents
Frequently Asked Questions
A complete well system in Montana typically costs $10,000–$30,000, depending on depth and geology. Drilling costs average $25–$65 per foot. A 150-foot PVC well costs ~$5,300; steel casing ~$12,600. Add pump ($2,000-$5,000), tank ($500-$1,500), testing, and the $250 DNRC filing fee.
Exempt domestic wells (≤35 gpm, ≤10 acre-feet/year) do not need a pre-drilling permit. However, you must file DNRC Form 602 (Notice of Completion) within 60 days after first use. The filing fee is $250. Wells exceeding 35 gpm require a Beneficial Water Use Permit (Form 600) before drilling.
Drilling itself takes only 1-4 days for most domestic wells. The complete process from scheduling to usable water typically takes 2-6 weeks, including driller scheduling, pump installation, testing, and paperwork. Add 2-6 months if a water-right permit is needed.
Yes. About 10% of Montana wells exceed health standards for arsenic. Hotspots include southwestern Montana, Madison/Missouri basins, and north-central ranges. The MSU Well Educated program recommends testing all new wells for arsenic, especially in known high-arsenic areas.
Montana does not mandate private well testing, but MSU Extension strongly recommends annual testing for total coliform bacteria and nitrate. Test for arsenic, manganese, and metals at initial installation and every 3-5 years. About 25% of Montana wells have bacteria; 3% exceed nitrate limits.
Are You a Licensed Driller?
Check out our compliance reference for Montana drilling regulations, licensing, and construction standards.
Montana Driller Compliance Guide →Sources & References
All facts in this guide are sourced from official Montana government agencies and university research:
- West Yellowstone Municipal Code §13.04 – Connection requirements
- Montana DEQ – COSA (Certificate of Subdivision Approval)
- 2024 Well Drilling Cost Averages
- Chambers Drilling Montana FAQs
- Montana DNRC – Exempt Well Requirements
- MSU Extension – Well Owner Responsibilities
- MSU Extension – Testing Private Well Water Quality
- MSU Well Educated – Data and Results Summaries
- EPA – Protect Your Home's Water
- Gallatin Local Water Quality District – Well Maintenance
- Montana Board of Water Well Contractors
- DNRC Regional Water Offices
- MSU – Certified Montana Drinking Water Labs
- DNRC – Water Right Forms and Resources
- Montana Water Well Drillers Association