Good Well Hunting

The water utility in Wisconsin’s capital city combs older neighborhoods to find old private wells as part of efforts to protect its groundwater supply.
Good Well Hunting
Most old wells Madison Water searches for are not this obvious or as picturesque. From left, Joseph Grande, water-quality manager; Marie Van Aartsen, water-quality program specialist; and Kevin Miller, water-quality aide, sit on a 1934 well built as a Depression-era project near the Lake Mendota shoreline. The city does not use it but honored a request from residents not to dismantle it.

Some people who live in older neighborhoods in Madison, Wis., are surprised to find Kevin Miller at their door, asking to look for a private well on their property.

Often their response is, “We don’t have a well. We’ve had city water for 30 years,” says Miller, a water-quality aide (and designated “well hunter”) with the Madison Water Utility. Sometimes those residents are wrong — they do have a well, an artifact of earlier times that while no longer in use creates a conduit to one of the aquifers that supply the city’s drinking water.

Finding and abandoning those wells is a part of Madison Water’s source water protection program. As long as old wells exist, they pose a threat of water supply contamination.

Miller finds them in the middle of backyards, next to garages and in basements. When he does, the homeowners receive orders to abandon them, with financial help from the city and sometimes the state Department of Natural Resources (DNR).

The well survey program began in 2010, the same year in which Madison Water tightened its well abandonment ordinance. Last December, the utility abandoned its 200th private well since the survey’s inception. Joseph Grande, water-quality manager, hesitates to estimate how many more wells might exist — it could be several hundred.

High-purity source

Madison is rich in water resources — the center of this city of 235,000 is  built on an isthmus between lakes Mendota and Monona — but it has relied on groundwater for well over a century. That’s because in the “bad old days,” the lakes were repositories for sewage and all manner of pollutants.

Source protection matters greatly because Madison residents drink groundwater after only minimal treatment. The utility has 22 deep wells scattered around the city, each with a capacity of about 3 mgd. The wells typically pump a total of 28-30 mgd, although summer usage can drive demand up to 40 mgd, and even 50 mgd in extreme drought.

“Each well has its own treatment,” says Grande. “We pump the water out, add chlorine and fluoride, and deliver it to distribution. We treat one well for iron and manganese removal. At another we recently added an air stripper to remove VOCs, in particular tetrachloroethylene [a dry-cleaning chemical]. The concentration is below the regulatory standard, but we saw it increasing and wanted to add treatment before getting anywhere close to the limit.”

The extra mile

Madison Water, a department of the city overseen by an appointed board, goes far beyond what’s legally required to safeguard its supply. An example is the utility’s all-inclusive approach to wellhead protection planning.

“We’re required by the DNR to have wellhead protection plans for wells drilled after 1992,” says Grande. “That means we need such plans for only three of our wells, but we decided some years ago to develop plans for all of our 22 wells.” To date, 19 of the plans have DNR approval and the remaining three are being prepared for submittal.

“Wellhead protection plans describe the local hydrogeology, the aquifers and their capacity, and they include data from modeling performed by the Wisconsin Geological Survey that identifies the well’s capture zone — the land area from which precipitation ultimately will make it down into the well within five years,” Grande says.

In addition, a zoning layer prohibits businesses that use hazardous chemicals (as defined by the U.S. EPA) from locating within wellhead protection areas. Such operations include dry cleaners, gas stations and car repair shops. The minimum protection zone is a 1,200-foot radius around the wellhead; it can extend farther based on the size of the five-year time-of-travel capture zone.

On the lookout

The well hunting program so far has given priority to the wellhead protection areas, starting in older parts of the city where records indicate that some homes are older than the water mains that now serve them.

A good example is the area around Well 14, an older section between University Avenue (which runs through the University of Wisconsin campus) and the shore of Lake Mendota. “In that case we looked beyond the wellhead protection zone because we knew we would find a high concentration of wells in that area,” says Grande. “Many were at summer cottages that when built did not need connections to the municipal water system. We wanted to be sure those wells were properly abandoned if they weren’t being used.”

Another case involves Well 7 on the city’s north side. There, a number of houses started construction in the late 1930s but were derailed by the onset of World War II, as building materials were redirected to the war effort. Many people lived in the unfinished homes and had private wells until municipal mains were installed in the 1940s. Other cases simply involve farmhouses in areas that developed into subdivisions as the city grew.

Why it matters

Old wells in these and other areas are potential avenues for groundwater pollution. While actual incidents may be rare, they can be severe. During one inspection, Miller found a washing machine discharge hose routed into what the owners thought was a floor drain but was actually a well casing. In another instance, an old well alcove in a basement had a vent pipe to the outside that a fuel oil delivery driver mistook for a fill pipe. Some residents have been known to dump used motor oil into old well casings.

Incidents like that help motivate Miller as he makes his rounds, generally from April through November when there is no snow to obscure evidence of wells. Letters are sent to notify residents of well inspections in their neighborhood. Miller sets out daily with a list of addresses and a map, in most cases looking in backyards for features such as a protruding casing, a concrete slab with a manhole cover in it, or a depression that might indicate the presence of a well pit.

At some homes, based on criteria that include the relative age of the house and the water main, Miller has instructions to check inside the house, as well. If no one is home, he leaves a door hanger. If someone answers the door, he explains what he’s up to.

Most homeowners he meets feel certain they have no well. “I persist and ask them to allow me to look anyway, and they do,” he says. “Many times I do find wells in those situations.” Sometimes it’s a casing that a previous owner cut down level with the concrete basement floor. Other times it’s an alcove — a room about 4 feet square — that once housed a well pump but is now used for storage.

Miller doesn’t disturb the home during inspections: “Sometimes I have to move a box or two. We typically don’t ask them to clean the basement so we can see every nook and cranny.” Finished basements hinder inspection, but Miller doesn’t pull up carpeting or ask people to open up drywall. Wells hidden behind improvements are unlikely to present contamination problems.

“I do indicate to people that if they do some remodeling in the future and find a pipe that’s not connected to something, they should call and have us look at it,” Miller says.

Taking action

If Miller finds a well, he gives the homeowner a variety of information, including a description of the reimbursement program and a list of well drillers and pump installers who are licensed for well abandonment. He also refers owners to the Madison Water website, where more information and answers to frequently asked questions are available.

“I recommend they contact a couple of the contractors and get bids on the job,” Miller says. “Once they decide on a contractor, that contractor calls us a couple of days before doing the work so we can be there to observe.”

Owners receive an official notice and order for the well abandonment. Typically the work must be done in 90 days, although the utility freely grants extensions for financial hardship, weather difficulties and other reasons. “We don’t want to make it more costly for them just so we can meet a deadline,” Grande says. “Giving them another two months will not increase the contamination risk dramatically. We tend to be pretty flexible as long as we know they’re working on it.”

The Madison Water program reimburses owners for half the well abandonment cost up to $1,000. Owners can also access the DNR’s income-dependent Well Abandonment Grant Program, which covers up to 75 percent of the cost.

“We didn’t want an approach where we said, ‘You welcomed us into your house to look for this well, and as a thank you we’re going to force you to abandon it at your own cost, which may be up to $1,200,’” Grande says. “We’re not trying to be punitive. We’re trying to protect the groundwater. A number of people have had their well abandonments paid for entirely by city and state funds.”

Well abandonment typically means filling the hole with bentonite clay pellets. The cost then depends on the well’s depth, which may range from 25 to more than 250 feet. “We sometimes find wells that are fully intact and could almost be plugged in and operated — the pump and wiring are still there,” Miller says. Naturally, those abandonments cost more. Sometimes concrete well pits must be collapsed and filled with pea gravel.

Grande says, “We are actually enforcing a state code, so if there is any doubt about whether we should allow a pit to remain or have it abandoned, we go to the DNR and ask for guidance. If a homeowner doubts our authority or questions our decisions, we go directly to the DNR and ask what they would tell the well owner to do.”

The road ahead

Madison Water has completed well surveys around seven of its 22 deep wells, starting around those where old private wells were most likely to exist. “We are unlikely to find many wells in the remaining wellhead protection areas, just based on the ages of the neighborhoods,” Grande says. “But when we expand beyond the wellhead protection areas, there likely will be significant areas that have unabandoned wells.”

Meanwhile, the utility has informed local real estate associations about its well abandonment program, and some calls for inspections come from agents or from owners of homes in the process of being sold.

The sheer number of property inspections around a municipal well can be substantial. The Well 14 area, which served as the pilot for the well hunting program, saw 802 homes inspected externally, and 304 of those inside, as well. The Well 7 survey included 543 external inspections, 170 of those also inspected inside.

In all, including wells abandoned in the years before 2010, Madison Water has closed off some 500 private wells. “There are still probably several hundred and maybe up to 1,000 more that we haven’t discovered yet,” Grande says. “On the other hand, we may only find 200 more.”

Whatever the case, Madison residents can feel confident their groundwater is being protected as old wells are sealed off, year by year, step by methodical step.  


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