In the summer of 2025, engineers lowered flow meters into Three Forks manholes for about two weeks and read the data from 3 a.m. to 5 a.m., the hours when almost nobody in a small town is running a faucet. In some of the basins they monitored, water was still moving at up to 81 gallons a minute. That is a lot of water at an hour when it should be close to zero, and most of it isn't coming from anyone's kitchen.
The engineering firm, Great West Engineering, told the City Council on September 9, 2025 that the town's treatment plant averages just over 400,000 gallons a day. A town this size should be sending it about 200,000. Much of the difference is clean water getting into pipes built for sewage. That includes groundwater pushed in by basement and crawl-space sump pumps. Engineers estimated 50 to 80 of those pumps were connected to the city sewer, and in April 2026 they put the figure at "somewhere around 80 homes."
For anyone buying or selling an older home in town, this comes down to one question about one house: where does the sump pump discharge go? Two things make that question matter in a Three Forks sale. The answer doesn't show up anywhere a buyer would normally look, and the city has now formally committed to going looking for it.
The bill that can't see the water
Three Forks calculates sewer charges from water use, not from sewer flow. According to the city's water and sewer rates page, the utility averages each household's water meter readings for December through March. Those are non-irrigation months, when most water is used inside the house. The average sets that customer's sewer rate, and it takes effect each July 1. The minimum charge is $54.25 for the first 400 cubic feet, plus $6.97 for each additional 100 cubic feet.
A sump pump doesn't draw from the water meter. It lifts groundwater out of a basement or crawl space. When that water goes into a floor drain or a sewer cleanout, the plant treats it, but the household's bill never registers it. The engineer laid out the cost side at the September 2025 meeting, as recorded in the council minutes:
"Rates are based off domestic use and we expect a home to put out so many gallons/day, and those sump pumps could be adding 3-4 times the normal water to be treated. Remember, it costs money to treat water, that's why we have rates."
So the cost doesn't stay with the house that creates it. It's shared across every sewer customer in town. And it uses up capacity the town has very little of.
Why a small capacity number makes this a town-wide question
At an April 14, 2026 special council meeting, Jessica Salo of Great West said the lagoon system is at capacity for biological loading at certain times. She estimated the system could handle 190 to 300 more people before it needs to expand. The same presentation used a projected growth rate of 2.6% a year, which puts the city's population at 3,782 by 2045. One council member responded, "300 people isn't very many. It's coming pretty quick."
The September 2025 draft had listed alternatives totaling about $14.2 million if every project were built. That included a $6.2 million treatment plant expansion. The final version came back softer. When the council adopted the revised Wastewater Preliminary Engineering Report on August 11, 2026 as Resolution #475-2026, Salo said the earlier population numbers had been "too conservative." An expansion will still be needed as the city grows toward its 20-year planning number, she said, "but it's not as dire as previously presented." She was not aware of any discharge permit violations.
What the revision didn't soften was the cause. In Salo's words from the August 11 minutes, "I&I [inflow and infiltration] is still the critical issue which the City staff will do some extra work on and correct those sump pumps and investigate with CCTV."
Every gallon of groundwater kept out of the pipes is capacity the plant can use for actual homes. Some deadlines are also closing in. The current discharge permit expires April 30, 2027. The engineer suggested reviewing whether rates are high enough to fund the chosen projects in 2027 to 2028.
What the camera work reaches
The plan is to run cameras through the pipes, a process called CCTV inspection. Great West recommended camera work on all the existing clay lines in 2026 to 2027, especially in the areas with the most infiltration. Those lines are among the oldest parts of town. The collection system was first installed in 1916 with clay tile pipe, and much of that clay was slip-lined in 2006. In May 2026, the Water/Sewer Committee reported that Public Works planned to use the city's own camera, and possibly borrow Manhattan's, to monitor flows and find sump pumps and other sources of inflow.
The city's records describe what a camera finding connects to:
- The rule itself. City Code §9-5-13(A) prohibits discharging groundwater, subsurface drainage, roof runoff and surface water into the city's sanitary sewers. The prohibition traces back to Ordinance 196 in 1980.
- The process. The code calls for written notice that describes the violation and allows a reasonable time to correct it. Continuing past that deadline is a misdemeanor under the city's general penalty section, and each day counts separately. A violator also becomes liable to the city for expense, loss or damage the violation causes.
- Access. The same chapter allows sewer personnel to enter connected properties to inspect, measure, sample or test, under its provisions.
- The pipe. The city's new resident page says property owners are responsible for all water and sewer pipes, fittings and connections on their property, all the way to the city's mains.
That fourth point is where the issue reaches a home sale. Leaking service lines were on the engineer's list of inflow sources alongside sump pumps, manhole lids and cracked pipe sections. The stretch of pipe between the house and the main belongs to whoever owns the house.
Some questions are still open, and the record says so. The council has discussed charging sump-pump users for the capacity they use, but members pointed out the obvious problem with charging for something the ordinance already bans. Staff noted that some pumps were installed before they were prohibited. No surcharge has been adopted. The published residential rate schedule has none, and the October 13, 2026 council packet lists grant closeouts for the engineering report but no sump-pump item. No inspection timetable for individual properties has been published.
Where the paperwork goes quiet
Most buyers in Montana receive the Montana Association of REALTORS® Owner's Property Disclosure Statement. The April 2026 edition lists sump pumps in its plumbing section and has a separate prompt for public sewer systems that clog or back up. The form asks about adverse material facts concerning those items. It doesn't ask directly whether a sump pump discharges into the public sewer. The cover statement also says the seller's agent isn't required to inspect the property or verify what the seller wrote.
The utility bill doesn't help either, for the reason covered above. A house whose pump runs into the sewer can have the same winter-average sewer charge as the house next door. So the routine documents in a Three Forks sale can be accurate and still say nothing on this point. The answer is in the basement, where the discharge line either runs outside or ties into the drain.
The city has also changed who carries utility accounts. As of January 1, 2026, new water and sewer accounts must be in the property owner's name or that of a written designee. Existing tenant accounts continue until certain transfer triggers occur. The city's new resident page also says owners are ultimately responsible for all charges at the service address, and unpaid charges can be recovered as a lien. Whoever the account is in, the charges and the pipe out to the main trace back to the owner.
A few direct questions
Is the city inspecting homes for sump pumps right now? The council records show a commitment to CCTV work focused on the clay lines and to correcting sump-pump connections. As of the October 13, 2026 packet, there's no published schedule of property inspections and no CCTV contract on record. Camera work on the mains is how the engineers proposed finding where clean water enters.
Does the rule apply to pumps installed decades ago? The ordinance prohibits the discharge itself and doesn't say when a pump was installed. City staff acknowledged in April 2026 that some pumps went in before they were prohibited, and the council has not settled how it will treat those cases. City Hall is the authority on how it applies to a specific property. American Legal Publishing also notes that its online code may lag the city's most recent ordinances.
Could sewer rates change because of this? The engineer suggested rates be reviewed in 2027 to 2028, once the city knows which projects it's funding. The camera results are meant to set those priorities.
If you're weighing an older home in Three Forks, or getting one ready to sell, the sump pump's discharge line and the sewer line out to the main deserve attention before an offer goes in. I'm glad to walk through the city's records with you and point you to the right people at City Hall. Reach out to Deirdre Quinn whenever you're ready. Let's Connect.
This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.
