What a Montana Well and Septic Inspection Covers (and Skips)

Two systems decide whether a rural Park County property works as a home, and neither one is in a standard home inspection. Here is what the well and septic inspections test, what they miss, and the two files to pull before anyone drives out.

If you are under contract on a Park County property with its own well and septic, the question to settle before the inspection deadline is what those two inspections cover, what they leave out, and which documents you should have in hand before the truck arrives. This post walks through both inspections piece by piece, the Park County rules that shape them, the water tests that matter here, and what the results mean for your offer.

What does a Montana well and septic inspection cover?

A well inspection covers four things: how much water the well produces, whether the water is safe to drink, the condition of the pump and pressure equipment, and the wellhead itself. A septic inspection covers the tank, the drainfield, and the permit record. Neither one is part of a general home inspection, and both start with paperwork, not a shovel.

The general inspector's report will say the taps run and the toilets flush. The rural home inspection post covers why that report stops at the foundation. This one goes deeper into the two systems that sit outside it, because the questions a buyer needs answered are specific: gallons per minute in August, what is in the water, how big the tank is compared with the house, and whether the drainfield was ever permitted.

The position this post takes: the most useful part of both inspections happens at a desk. The well log and the septic permit file tell you what was built, when, and to what standard, and they are free. An inspector who arrives with those two files in hand tests the right things. One who arrives without them is guessing at what is underground.

What should you pull before anyone drives out?

Two files, both public and both free: the well log from the state's groundwater database, and the septic permit file from Park County's online archive. Together they answer the depth and yield of the well when it was drilled, the size and type of the septic system, and whether either was permitted at all. This is the two-file pull, and it takes an evening.

File one, the well log. Every well drilled by a licensed contractor in Montana is supposed to have one on file. The state's prospective well owner guide, published by the Board of Water Well Contractors and last revised in 2007, says state law requires the driller to submit a copy of the well log to the Montana Bureau of Mines and Geology within 60 days of completing the well, and to give a copy to the owner. Those logs live in the Ground Water Information Center, the bureau's central repository, which holds well-completion reports from drillers along with water-level and water-quality records. Create a free login, then search by owner name, address, or township, range and section. MSU Extension's guide to finding a well log walks through each search and notes that the log carries the depth, the water level, and the geologic material around the well. Write down the GWIC ID. The inspector will want it.

A property with no log in the database is not disqualified, but it is a flag. Older wells, hand-dug wells, and wells drilled by someone who never filed all show up as blanks. Ask the seller for their copy, and if none exists, tell the inspector so the flow test and the casing check get more weight.

File two, the septic permit. Park County requires a permit to construct, alter, or repair a septic system, under Section 4.1 of the county's Onsite Wastewater Treatment Regulations (revised 2012, with later fee updates), and Section 7.1 requires the county to inspect every permitted system before it is backfilled, barring a specific exception from the county. The permit file is the record of that. The county's Environmental Health page links to an online archive of septic permits with a public login posted right on the page. Search the property, and download whatever is there: the application, the site evaluation, the drawing showing where the tank and drainfield sit, and the inspection sign-off.

A system with no permit on file was either installed before the county required one or installed without one. Either way, the county has no record of looking at it, and the inspection has to do the work the permit file would have done.

Here is what each file tells you and where to get it:

Two of those rows need a word. The water right line matters because a domestic well in Montana is exempt from the permit process only within limits. Under MCA 85-2-306, a well outside a stream depletion zone that pumps 35 gallons a minute or less and does not exceed 10 acre-feet a year needs no permit, but the appropriator has to file a notice of completion with the state within 60 days of putting the water to use, a second 60-day clock separate from the driller's well-log deadline. The same statute says a combined appropriation from the same source by two or more wells exceeding 10 acre-feet needs a permit regardless of flow rate. The DNRC booklet is blunt that the driller's well log report does not count as that filing; the owner has to do it. You can check whether it was done in the DNRC Water Rights Query System, which searches by owner name or the property's geocode. A missing filing is fixable, but you want to know it before closing, and the water rights post covers why the paper right and the physical water are two different things.

The certificate line applies to lots under 20 acres. Montana's Sanitation in Subdivisions Act, at MCA 76-4-102, defines a subdivision as a division of land creating one or more parcels under 20 acres, exclusive of public roadways, and those parcels go through a state sanitation review. Park County's own septic regulations ask permit applicants for a copy of the Certificate of Subdivision Approval and the approved lot layout where one exists. On a parcel that size, that certificate is the drawing that shows where a replacement drainfield was supposed to go.

What does the well inspection test?

Four things: yield, water quality, equipment, and the wellhead. Yield is measured in gallons per minute over a timed test. Water quality comes from a certified lab. Equipment means the pump, pressure tank, switch, and wiring. The wellhead check covers the casing, cap, seal, and the distances from the septic system. Ask for all four in writing before the visit.

Yield. When the well was drilled, the contractor was required to test it. The DNRC guide says water well contractors must test yield for at least one hour on any well pumping 100 gallons a minute or less, and that most lenders want a longer test. The number on the log is the yield on drilling day; the inspection measures it today. Two benchmarks help you read the result. The federal floor for an FHA loan, in HUD Handbook 4000.1, is a continuous flow of at least three gallons per minute for an existing well and five for new construction, and its shared-well rules spell out the test as a continuous four-hour period, with 720 gallons of pressurized storage accepted for an existing dwelling when the well itself yields less. The DNRC guide's own planning figure is higher: an average household uses about 200 to 400 gallons a day, and for a household of four it suggests a dependable yield of 10 to 25 gallons a minute to cover everything including lawn and garden, adding that much smaller yields can work with adequate storage. So a three-gallon well can clear an FHA appraisal, though the DNRC guide notes most lenders want at least five, and a ten-gallon well is comfortable for most households. The gap between them is where storage tanks and irrigation plans live.

Ask when the test was run. A well in Paradise Valley that produces well in May, with the snowpack still feeding the aquifer, can tell a different story in late August after a dry summer. If your inspection lands in fall, after a dry summer, the number you get is closer to the lean end of the year than a spring test would be, which is the number you want.

Water quality. Montana does not enforce drinking water standards on private wells, so testing is on the buyer. MSU Extension's water quality specialist, writing in the Winter 2023 issue of Lives and Landscapes, reports what the state's Well Educated program has found across years of samples from owners who chose to test, statewide: total coliform bacteria present in about 25 percent, E. coli in about 3 percent, nitrate above the drinking water threshold in about 3 percent, and arsenic and manganese above health thresholds in about 10 percent of wells tested. The recommendation is to test every year for bacteria and nitrate, and to run a complete list of parameters the first time. The program's statewide parameters of concern, listed on its county guidance page, are arsenic, fluoride, nitrate and nitrite, selenium, uranium, lead, and copper. Most of those have no taste or smell.

One trap: the Well Educated program's discounted kits, per the Gallatin Local Water Quality District, cannot be used for testing tied to a real estate transaction. For a purchase you go to a certified lab directly. Park County makes that easy. The Environmental Health office at 414 East Callender Street in Livingston hands out sample bottles for Bridger Analytical Lab in Bozeman and accepts samples on Monday mornings before noon, per the county's well water testing sheet. The Montana State Environmental Laboratory, run by the state health department, is the other certified option, with request forms online and a package for HUD and FHA loans.

Here is what the tests cost, from the two labs' current published sheets:

Both labs date their sheets and say prices can change, but the scale is the point: a full first-time panel runs about $300 to $340 at either lab, and the bacteria and nitrate screen costs less than dinner in Livingston. Please order the complete panel on a purchase. Arsenic and manganese sit above health thresholds in about one in ten Montana wells tested, and the only way to know is the lab.

Equipment and the wellhead. The inspector runs the pump, watches the pressure tank cycle, checks the pressure switch and the wiring, and looks for corrosion, a cracked cap, or a casing that sits at or below grade where surface water can run in. The setback check uses the state's table in ARM 17.36.323, amended effective December 2023, which Park County also carries as Table 3 of its regulations: an individual well sits at least 50 feet from a septic tank and 100 feet from a drainfield, and 100 feet from surface water. On an older property the well and the drainfield were placed by whoever dug them, and a tape measure sometimes finds a well 60 feet from a drainfield that a bacteria test then confirms. The land survey post covers why a survey and the septic drawing should be read together on any parcel with a shared boundary.

What does the septic inspection check?

A real septic inspection opens the tank. The EPA's checklist for buyers covers pumping records, the system's age, sludge and scum levels, signs of leakage or backup, the integrity of the tank and its inlet and outlet, the drainfield for standing water, the distribution box, and whether the records match local rules. A visual look at the lids with the tank still full covers almost none of that.

The EPA's New Homebuyer's Guide to Septic Systems, published August 2017, is the clearest short description of the job, and its checklist is what you should ask a Park County inspector to follow. A few of the items deserve translation:

• Sludge and scum levels. The inspector measures how much solid has settled and how thick the floating layer is. Those numbers say whether the tank has been pumped on schedule, and the EPA guide says a typical tank is pumped about every three to five years, with the EPA's maintenance page adding that systems with pumps, float switches, or other mechanical parts should be inspected about once a year.
• Integrity of the tank, inlet, and outlet. A missing or broken baffle lets solids into the drainfield, which is how drainfields fail. The tank has to be pumped for the inspector to see the baffles, which is why a pump-and-inspect costs more than a look.
• The drainfield. Standing water, unusually green grass in a dry September, or a sewage smell are the field-level signs of failure the guide lists. An inspector will also probe the field and, on many jobs, run water into the system for a set period and watch how it takes it.
• Records against local rules. This is the permit file from the two-file pull, and the place the inspector checks the tank size against the house.

That last item is where Montana's design standard comes in. Park County adopts Circular DEQ-4, the state's standard for subsurface wastewater systems, by reference. The December 2023 edition sizes residential tanks by bedroom: a minimum of 1,000 gallons for one to three bedrooms, 1,500 for four or five, and 2,000 for six or seven. Design flow is set the same way, 300 gallons a day for a three-bedroom home. And the definition section says an unfinished basement counts as an additional bedroom. So a listing that describes a four-bedroom home with a finished basement, sitting on a permit that says a 1,000-gallon tank for a three-bedroom house, has a mismatch the inspector should name, and it is a mismatch that shows up regularly in older Park County homes that were added onto over the years. An existing system is not out of compliance for missing today's numbers, but the gap matters the day it needs repair or replacement, because the replacement has to meet them.

Age matters too. The EPA guide puts the average lifespan of a septic system at 15 to 40 years with proper maintenance, a range wide enough that the permit date alone does not tell you much. A 1985 system with pumping receipts every four years is a different asset from a 1985 system nobody has opened.

What does Park County require, and what does it not?

Park County requires a permit to build, alter, or repair a septic system and a county inspection before the system is buried. It does not require an inspection when a property sells. Montana's seller disclosure law requires the seller to disclose known problems with the water source and the wastewater system, but not to investigate them. The inspection at sale is the buyer's to order.

The permit rule is Section 4.1 of the county regulations: it is unlawful to construct, alter, or repair an individual sewage treatment system in Park County without a valid permit from the health officer. Section 7.1 requires that every permitted system be inspected by the county before backfilling, with 48 hours' notice from the installer. The county's wastewater fee schedule, posted as the August 2024 schedule and superseding the fee table printed in the 2012 regulations, lists $300 for a new system installed by a licensed installer, $200 for a replacement, upgrade, or connection, and $300 for a site visit. Permits for new systems expire if the system is not installed and approved within two years; permits for repairs and replacements are valid for three months. Those fees are the county's paperwork cost, not the system cost, which depends on soils, setbacks, and the design the site evaluator can fit on the lot. The county posts current lists of licensed site evaluators and licensed installers, and a homeowner can install a system on their own residence after passing the county's exam.

What the regulations do not contain is any provision for inspecting an existing system when the property changes hands. Nothing in them requires a seller to have the tank pumped, the field checked, or a certificate issued. Montana has no statewide point-of-sale septic requirement and Park County has not adopted one, which means the county's file on a property may end the day the system was backfilled, thirty years ago.

The disclosure law fills part of that gap. MCA 70-20-502 requires a seller of residential property to disclose adverse material facts they have actual knowledge of, and its list names matters affecting the water source serving the property and matters affecting the system for wastewater treatment. It also says the seller and the seller's agent are not obligated to investigate, and it covers residential property only, so on bare land with a well there is no statutory disclosure form at all. A seller who never had the tank pumped and never noticed the field can sign that form in good faith. The disclosure tells you what the seller knows; only the inspection tells you what is true.

Here is the cost picture for the whole check, with the sources and their limits:

Every one of those numbers moves with the property. An inspector driving from Bozeman to Gardiner charges for the drive. A tank buried four feet deep with no risers costs more to open than one with lids at grade, which is why the state standard the county adopts, DEQ-4, requires inspection ports above the inlet and outlet and access extended to within 12 inches of the finished ground on new tanks. Please get quotes for the specific property, not the county average.

What do the results mean for your offer?

Three outcomes: the systems pass, the systems need a fix, or a system needs to be redesigned. The first costs you the inspection. The second is a repair credit or a seller repair before closing, inside the inspection contingency. The third changes what the property is, and the price should follow.

A low-yield well is usually a storage problem, not a walk-away. A cistern and a larger pressure tank usually turn a three-gallon well into a house that runs fine, provided the lender accepts the setup, and the 720 gallons of pressurized storage HUD accepts in its shared-well rules is a useful benchmark for how much. Irrigation is the exception. If the plan is a lawn and a garden on a three-gallon well, the plan has to change.

A failed water test splits two ways. Bacteria can come from a bad cap, a cracked casing, or a well too close to the drainfield, and the fix ranges from shocking the well to repairing the wellhead to a new well. Arsenic, uranium, or nitrate come from the aquifer or from what is above it, and the fix is treatment at the tap or at the whole house, an ongoing cost that belongs in your numbers. Ask the lab for the number, not just pass or fail, because the difference between slightly over and far over is the difference between a filter and a redesign.

A failing drainfield is the expensive one. The permit for a replacement costs $200 at the county when a licensed installer does the work, and the system costs whatever the soils and setbacks allow, which is why the site evaluator's report matters more than the installer's quote. On a small lot, the question is whether a replacement field fits at all inside the 100-foot well setback and the 10-foot property line setback. That is a question to answer before you remove the contingency, not after.

Two honest tradeoffs. A seller who pumps the tank the week before the inspection has made it easier to see the baffles and harder to read the sludge history, so ask for the pumping receipt and its date. And a pass on a well test in October carries more weight than a pass in May, when the aquifer is at its fullest. If the timing lands in spring, ask the seller for last August's experience in writing, the same way the road post suggests asking about last winter's plowing.

Do this week, on any property you are serious about: create the free groundwater database login and find the well log, open the county's online permit archive and download the septic file, and call Park County Environmental Health at (406) 222-4145 with the address to ask whether anything in the file is newer than what is online. Then book the well and septic inspections for the same visit, with the two files sent ahead. That order, paper first and truck second, is what keeps both inspections inside the same fall deadline as the rest of the property checks, and it is the difference between a report that tests the right things and one that tests whatever the inspector could find.

Frequently Asked Questions

What does a well inspection cover in Montana?

A well inspection measures the well's yield in gallons per minute over a timed test, samples the water for a certified lab, checks the pump, pressure tank, pressure switch and wiring, and examines the wellhead: casing, cap, seal, and the setbacks from the septic tank and drainfield. It is a separate service from a general home inspection, and it starts with the well log from the Montana Bureau of Mines and Geology's Ground Water Information Center.

How do I find the well log for a property in Park County, Montana?

Search the Ground Water Information Center at mbmggwic.mtech.edu, run by the Montana Bureau of Mines and Geology. Create a free login, then search by owner name, address, or township, range and section. Montana law requires the driller to file the log within 60 days of completing the well. The log shows the depth, water level, yield at drilling, and the geologic material around the well. Record the GWIC ID for the inspector.

How many gallons per minute should a well produce in Montana?

HUD Handbook 4000.1 sets the FHA floor at a continuous three gallons per minute for an existing well and five for new construction, and its shared-well rules describe the test as a continuous four-hour period, with 720 gallons of pressurized storage accepted for an existing dwelling when the well yields less. The DNRC's prospective well owner guide suggests a dependable 10 to 25 gallons per minute for a household of four that irrigates a lawn and garden, and says smaller yields can work with adequate storage.

What should I test well water for when buying a house in Montana?

MSU Extension recommends testing for bacteria and nitrate every year and running a complete panel the first time. Its statewide parameters of concern are arsenic, fluoride, nitrate and nitrite, selenium, uranium, lead, and copper. Well Educated program samples have found coliform bacteria in about 25 percent of Montana private wells and arsenic or manganese above health thresholds in about 10 percent. For a purchase, use a certified lab such as Bridger Analytical Lab or the Montana State Environmental Laboratory; the discounted Well Educated kits cannot be used for a real estate transaction.

What does a septic inspection include?

The EPA's homebuyer guide lists what an inspector checks: pumping and maintenance records, the system's age, sludge and scum levels in the tank, signs of leakage or backup, the integrity of the tank and its inlet and outlet pipes, the drainfield for standing water, the distribution box, and whether the records show the system complies with local rules. The tank has to be pumped for the inspector to see the baffles, so a pump-and-inspect covers more than a visual check.

Does Park County require a septic inspection when a house sells?

No. Park County's Onsite Wastewater Treatment Regulations require a permit to construct, alter, or repair a septic system and a county inspection before backfilling, but they contain no provision for inspecting an existing system when a property changes hands. Montana's seller disclosure law, MCA 70-20-502, requires a seller of residential property to disclose known adverse material facts about the water source and the wastewater system, and states that the seller is not obligated to investigate. The inspection at sale is the buyer's to order.

How big should a septic tank be for a three-bedroom house in Montana?

Circular DEQ-4, the state standard Park County adopts by reference, sets a minimum septic tank capacity of 1,000 gallons for one to three bedrooms, 1,500 gallons for four or five bedrooms, and 2,000 gallons for six or seven, using a design flow of 300 gallons a day for a three-bedroom home. The December 2023 edition counts an unfinished basement as an additional bedroom, so a home that was expanded after the permit may have a tank sized for a smaller house.

---

This article is general information, not legal, tax, or accounting advice. Stacy Bennin Real Estate is not a law firm or an accounting firm, and nothing here should be treated as advice from one. Laws, tax rules, and programs change, and they vary by state and by situation. Before acting on anything covered here, consult a licensed attorney and/or a certified public accountant in your state for current guidance on your specific circumstances.

---

Every rural property here runs on two systems the seller rarely thinks about and the buyer has to live with. If you are under contract on a place with its own well and septic and want help running the two-file pull before the inspection deadline, please reach out. Most of it is an evening at a desk and one call to the county, and it is much easier to read the results with the paperwork already in hand.

Stacy Bennin is a licensed real estate broker in Montana, affiliated with Legacy Lands Real Estate in Paradise Valley. She helps buyers and sellers across Park County and southwest Montana find property that fits their needs, and stays current on AI and emerging technology so her clients benefit from where real estate is headed, not just where it has been. Reach her at stacybennin.com or (406) 224-3267.