"Gatorade." That's how Amanda McQuaid, director of the UNH Lakes Lay Monitoring Program, described the color of Lake Kanasatka in the summer of 2020. By 2023 it was worse. "This whole area was solid green, scummy, like, thick," she told the New Hampshire Bulletin, and some of that water spilled over into Lake Winnipesaukee.

This past summer, a waterfront resident called it a "beautiful" year on the lake. Most of the credit goes to the 2024 alum treatment, and that part of the story is fairly well known around Moultonborough. Fewer people know what the treatment can't do. The phosphorus that feeds new blooms comes in from the surrounding land, mostly with rainwater, and the treatment doesn't touch it. That makes Kanasatka's clear water depend more and more on culverts, driveways, septic systems and shoreline plantings, and on the volunteers working on them.

What the Alum Actually Fixed

The Bulletin's September 25, 2026 report explains how it works. The Lake Kanasatka Watershed Association put alum into the water. The alum binds with phosphorus and settles to the lake floor. McQuaid said the treatment goes after nutrients that had built up over many years in a badly affected lake. It doesn't target the cyanobacteria directly. Scientists hope the effect lasts at least a decade, and experts including McQuaid have said it isn't permanent.

The before-and-after numbers show how much buildup there was.

The 2025 figures come from UNH's Lake Kanasatka 2025 Water Quality Highlight Report. It covers samples taken between May 29 and October 23, 2025. In the same report, chlorophyll-a averaged 3.8 ppb, which puts it in the middle tier. Dissolved oxygen measured on September 15, 2025 in the deeper layers between 8 and 13 meters still fell in the eutrophic range. By most measures the lake improved a lot, though not on every one.

The Phosphorus That Still Gets In

Improvement came gradually. The waterfront resident recalled blooms in 2025, including one in September. The state's records agree. NHDES logged a bloom report on May 30, 2025, a watch on June 6 and a warning on June 10 that stayed in place until June 25. It logged another report on September 19 and a watch on September 23 that wasn't lifted until December 10.

So what made 2026 different? McQuaid said the occasional cyanobacteria "blips" still happen and often follow heavy rain, which washes nutrient-laden runoff into the lake. This summer's rainstorms were mild. Blooms were also less severe on many lakes this year, and she described the alum as likely only part of the explanation for Kanasatka's good season.

She also named a third factor. Residents had stepped up their prevention work, including better stormwater management on their properties and nearby roads. The alum dealt with phosphorus that was already in the lake. The rain-driven blips come from phosphorus that's still arriving, and only work on land can slow that down.

Where the Watershed Association Is Putting Its Effort

The Lake Kanasatka Watershed Association's 2026 newsletters show where that land-side work is happening. As of June 2026:

• Burton Road and Foster Drive. A NHDES Section 319 grant project aimed at runoff from these roads was set to begin construction soon after Labor Day 2026. The association hasn't yet reported publicly on whether work has started.
• Sandy Cove and Glidden Road. A separate stormwater design, backed by a $150,000 Congressionally Directed Spending grant through the Lake Winnipesaukee Alliance, was being revised after feedback from stakeholders.
• Boots on the Ground. Since the program began in May 2023, 66 volunteers have completed 27 projects.
• LakeSmart. Forty properties around the lake had earned LakeSmart status and nine more were in process. Laurence Pizer serves as the lake's LakeSmart ambassador.
• Septic help. The association offered a 2026 septic inspection assistance application. The treasurer reported $759.50 in reimbursements under the 2025 program.

Septic was also on the agenda at the association's annual meeting on July 11, 2026, held at Moultonborough Academy. Steve Ellis gave a presentation on septic health, and the meeting included a board election and a question-and-answer panel. A recording of the meeting is now on YouTube. Septic systems near the water get attention across the Lakes Region, and our earlier post on the septic rule that now follows Tuftonboro lakefront buyers covers the state side of that issue.

The July newsletter's treasurer's report listed $37,521 in Watershed-Based Management Plan expenses, covering grant-project bills, UNH testing and analysis, and consulting. In the NH Gives campaign, 45 donors raised $7,998, enough for more water-testing equipment and parts for the loon camera.

Why Kanasatka Could Afford a Second Act

Kanasatka's treatment cost about $600,000. A $500,000 state grant covered most of it, and that grant used up half of the $1 million the Legislature first put into the Cyanobacteria Mitigation Loan and Grant Fund in 2023. The Lake Kanasatka community raised more than $400,000 on its own. Once the treatment was paid for, the association put the rest toward more prevention work. "That put us into such a great position," said Kirk Meloney, who led the association as president when it made the decision.

Other lakes may not find money that easily. The state fund grew to $2 million total and has paid for 11 projects, and as of April 2026 it had about $200,000 left. The Bulletin reported that several attempts in the Legislature to refill it were voted down or sent to study committees.

McQuaid has been direct about whether other lakes should copy Kanasatka's approach.

"We don't want everyone to be like, 'Oh, let me try to do that now,' because it's not going to work."

She described stormwater management and similar prevention as a good fit for most lakes. The alum treatment is far more specialized. That leaves Kanasatka in an unusual spot. It already used the expensive fix, the state fund that paid for it is nearly empty, and the most useful work left is the kind that happens on individual lots and roadsides.

Meloney remembers that the decision felt risky. "It was a concern to me, dumping all this stuff into this precious water body," he said, but he wanted to "listen to the science." The 2023 blooms reached Lake Winnipesaukee too. NHDES says water from Kanasatka drained into the big lake and contributed to similar conditions in Blackey Cove. Work in the Kanasatka watershed helps more of Moultonborough's water than one small lake.

The Lake This Fall

When McQuaid's team visited on Thursday, September 24, a loon and its chick were on the water while a bald eagle called from the pines overhead. Her crew lowered a cone-shaped net from a pontoon boat and brought up typical algae and zooplankton, which she described as signs of a healthy ecosystem. "A good base of the food web supports the fish, supports the loons," she said.

Volunteers keep the loon part going as well. This year's Loon Nest Cam was running by June, with loons seen near the nesting platform in Kilnwood Cove. Mark Whary installed the loon raft for many years, paddling a canoe with the heavy raft on top, and Scott Apgar has now taken over the job. Volunteer sampling teams collect samples on Kanasatka and Wakondah as part of the association's work with UNH. In 2025 those sampling dates ran into late October.

If you want to see it for yourself, the lake's one public access point is the boat launch and parking area by the dam on Route 25. Before you swim or put a dog in the water, check the state's Healthy Swimming Mapper, which NHDES updates daily. The older Kanasatka history page was last updated April 22, 2026, before this season began. For the association's newsletters and septic assistance details, go to kanasatka.org. Updates on the Burton Road and Foster Drive project will likely appear there first.

If you own on Kanasatka or elsewhere around Moultonborough and want a straight answer on your septic system, shoreline plantings or drainage before your next sale or purchase, Costantino Real Estate works on these lake-specific details every week. Reach out, or start with our Winnipesaukee water access page.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.