Landowner Finds the City’s Underground Water and Sewer Lines Crossing Her Property — Then the Court Rules the City Earned a Prescriptive Easement

Photo credit: AI-generated image created using ChatGPT. Illustrative only

It started the way a lot of property nightmares start: with something buried that nobody thinks about until it breaks. In Twin Falls, Idaho, a water-main rupture in 2018 didn’t just make a mess — it damaged a manufacturing building and disrupted work, then turned into a long fight over whether the city had any right to have pipes running under private land in the first place.

The owner, Christy Hamilton, and Hamilton Manufacturing, Inc. (HMI) argued the city’s underground water and sewer lines were essentially trespassing. But the Idaho Supreme Court ultimately sided with the City of Twin Falls, finding the sewer line was covered by an old written easement and the water line had become a legal right through long use — a prescriptive easement. The details are laid out in the court’s opinion.

The buried problem that turned into building damage

Hamilton owns three adjoining parcels near Rock Creek Canyon and operates the family’s long-running business there. Two separate city utilities ran under two different parcels: a water line under the West Parcel and a sewer line under the East Parcel.

The water line was the one that kept coming back like a bad habit. It dated to 1918, part of Twin Falls’ municipal waterworks project, and by 2018 it was old enough that a failure wasn’t shocking — except for where it happened and what it hit.

When the line ruptured in June 2018, the leak and the city’s excavation work damaged the HMI manufacturing building and interrupted operations. During repairs, the city also relocated portions of the line, which only raised the temperature on an already ugly dispute: was the city repairing its own infrastructure, or digging around on land it didn’t have rights to?

“We knew there were lines,” then the paperwork got weird

This wasn’t a case where a landowner claims they had no idea anything was there. The record showed the family had been dealing with these underground utilities for decades, including restrictions on what they could do near the canyon and lines.

Architectural drawings for a late-1970s expansion identified “Sewer & Utility Easement(s)” in the area where the disputed water line ran. And when Gene Hamilton (Christy’s father) sought approval in 1979 to put fill into Rock Creek Canyon, the planning commission approved it with a condition: the fill could not cover the city’s water and sewer lines.

That kind of condition is the sort of thing property owners remember — because it changes how you use land. It’s also the kind of detail that later becomes Exhibit A when everyone argues about whether the city’s presence was “open and notorious” and whether the owner had knowledge.

The water line kept breaking — and the city put its claim in writing

The water line didn’t just quietly exist underground. It repeatedly failed near the northeast corner of the manufacturing building, with breaks documented in 1984, 1986, and 2000.

The 1984 break eroded the canyon wall and exposed much of the pipe. After the 1986 break, the city sent Gene Hamilton letters blaming fill placed over the line. One warned repairs could cost as much as $5,000 and said the city intended to uncover the line and remove fill from the easement.

The second letter cut even closer to the heart of the later lawsuit: it told him his own plans and permit showed the utility easement and prohibited fill around city utility lines. In homeowner terms, it’s the moment when the city isn’t “asking nicely” anymore — it’s telling you that your land use is limited because it believes it has a right-of-way under your feet.

The sewer line fight came down to a missing map and one stubborn pipe

The sewer line under the East Parcel had a different backstory. In 1947, Isaac and Mabel Peterman granted Twin Falls an express easement to install and maintain a sewer trunk line on property that included what later became Hamilton’s East Parcel.

There was a catch that sounds minor until you’re in court paying lawyers: the 1947 easement said the line would follow a route shown on a “master map” kept by the city engineer — and nobody could find that map. Both sides’ surveyors searched for it before trial. No luck.

HMI argued that without the map, the city couldn’t prove exactly where the easement was supposed to run. They also argued the document was too vague and pointed to how it referenced a different tax parcel number.

But there was another practical problem that made the “maybe it runs somewhere else” argument hard to sell: there appeared to be only one sewer line in the relevant area, and it was under the Recycle Center building. Back in 1978, Gene Hamilton had pulled a permit to build a warehouse on the East Parcel, and the permit specifically required him to move the sewer line from under the building.

Gene and the city even signed an agreement allowing relocation in exchange for a new easement. Yet the sewer line beneath the building was apparently never moved. It stayed in place, and it kept operating for decades.

The Idaho Supreme Court said the 1947 agreement still had the basic requirements of a valid express easement — it identified the burdened property and showed intent to create a utility right — and the missing map didn’t kill it. Even if the map would have been more precise, the court leaned on how the parties performed over time, and the reality that there wasn’t evidence of an alternative sewer route. The line under the building was treated as the line contemplated by the easement.

The court’s bottom line: one easement was written, the other was earned

For the sewer: the court upheld that Twin Falls has an express easement for the sewer line beneath the East Parcel (under the Recycle Center). That ruling was enough that the Supreme Court didn’t need to decide whether the city also had a prescriptive easement for that same sewer line.

For the water: the city relied on a prescriptive easement — a right gained through long-term, open, continuous, adverse use with the owner’s knowledge. HMI argued that when the city installed the line in 1918, the land was wild, unenclosed, and unimproved, and Idaho law can presume use of that kind of land is permissive at the beginning.

Even assuming it started permissively, the courts found the city’s claim turned unmistakably adverse later. The key years were the late 1970s and 1980s, when the city not only required the Hamiltons not to cover the lines with fill, but also sent letters asserting easement rights and blaming the owner’s actions for breaks.

Timing mattered too. Idaho’s prescriptive period used to be five years (it didn’t increase to 20 years until 2006). The court said Gene Hamilton knew about the line from at least 1978 through 1999, and the city had clearly asserted its adverse claim by no later than 1986 — well beyond the five years required at the time.

HMI also argued the city destroyed any prescriptive rights by shifting parts of the water line during the 2018 repair. The trial court found one relocated section stayed within an existing express easement, and another moved by no more than about four inches while remaining inside the same underground rock support structure as the old pipe. The Supreme Court accepted those findings and declined to reweigh conflicting testimony.

Finally, HMI tried a technical argument many property owners will recognize: “Fine — if you say there’s an easement, then write down exactly where it is.” The Supreme Court said that level of survey-style specificity is typically required when a judgment is creating an easement, but here the court was deciding whether existing rights defeated trespass and nuisance claims, and the city hadn’t counterclaimed to quiet title and formally establish the easements in that way.

How people react when they hear “the city has pipes under your land”

When stories like this circulate among property owners, the reactions are usually less about legal theory and more about practical survival: people talk about old drawings, permit conditions, letters, and any scrap of paper that proves what everyone knew and when they knew it. Here, the city’s old correspondence and the planning commission’s fill condition mattered because they showed the owner wasn’t in the dark — and the city wasn’t acting like it needed permission.

Others tend to focus on the hard lesson about building over utilities. The Recycle Center piece is the kind of thing that makes contractors and long-time homeowners wince: a permit requiring the sewer line to be moved, an agreement signed to relocate it, and then decades later the same line is still apparently under the building. Whether that happened through oversight, cost, logistics, or “we’ll deal with it later,” it’s exactly the kind of buried decision that can surface at the worst possible time.

The Supreme Court affirmed the district court’s rulings across the board. For Hamilton and HMI, that means the remaining trespass and nuisance theories tied to those underground lines didn’t survive — and the city kept its utility rights under both parcels, attached to the land, not the owner. And for every landowner who’s ever wondered what’s really running under their yard, it’s a reminder that sometimes the oldest part of your property isn’t the house or the fence line — it’s what the city put underground generations ago.