The phosphorus at the bottom of Highland Lake has been climbing for twenty years. Some of that is old leach fields along the shore that quietly quit. Fixing yours is usually cheaper than you think, and sometimes it isn’t.
Highland Lake has been in the state’s Volunteer Lake Assessment Program for close to two decades, and the volunteers have been careful about it. What the record shows is a 211-acre cold-water lake that’s still borderline oligotrophic — clear, trout-stocked, good — with one number going the wrong way. Phosphorus in the deep water has gone up significantly since the sampling started. The lab language for that is internal loading: when the bottom goes anoxic in late summer, the sediment lets go of phosphorus it’s been storing. Where did the sediment get it? Runoff, mostly. And, for a long stretch of years before anybody was measuring, from septic systems on the shoreline that were put in when the camps were, and had stopped treating anything by the time the camps got winterized.
That’s the backdrop for a repair call on the East Andover side. A leach field that’s given up doesn’t announce it. There’s no smell most of the time, no puddle, nothing on the lawn — effluent that isn’t being treated in the soil is going somewhere, and on a lake lot the somewhere is downhill. The thing you notice, if you notice anything, is a tank that’s always full when it gets pumped. Or a toilet that’s a hair slower in August than it was in May. That’s the point to call. Not after the backup.
Here’s where Andover repair gets interesting, and it’s the reason we don’t say “replace it” as a reflex. On a shoreland lot, a new leach field has to sit back from the water — seventy-five feet at the very least under RSA 483-B, and a hundred or a hundred and twenty-five where the soil drains poorly. Plenty of the original camp lots on Highland don’t have that. A lot of them have ledge, or a well in the way, or a neighbor’s well in the way. So a full replacement on those lots isn’t a bigger version of a repair; it’s a design problem with a state permit and a bill that starts with a two. Which makes a repair that buys the existing field another decade — a d-box reset, a crushed line replaced, an outlet baffle that finally lets solids through fixed — worth a lot more here than it would on a two-acre lot off Route 4 with sandy soil and room to spare.
Andover camp owners: before you winterize, run water for five minutes and go look at the tank lid area and the field. If the ground over the field is soft and the rest of the yard isn’t, that’s the field telling you something before the ground freezes and it can’t. Cheaper to hear it in October than in April.
Rank order, from what we see in this town. First: the distribution box. It’s a small concrete or plastic box past the tank that splits the flow among the field lines, and it settles, tilts, and sends everything down one line until that line is drowned and the rest are bone dry. Fix is to dig it, re-level it, sometimes replace it, and put in leveling devices so it stays fair. Half a day. Second: the outlet baffle or tee inside the tank rots off — steel ones especially, concrete ones eventually — and solids that were supposed to stay in the tank start leaving. That silts the field from the inlet end. Fix is a new tee and a filter, an hour, and if we caught it early the field recovers.
Third: a pipe. Root intrusion from the maples every camp has, a line crushed by a truck that parked where nobody should’ve parked, a bellied section that holds water and freezes in January. We locate it, cut it out, replace it. Fourth: the field itself, saturated. And this one takes judgment. In 2023 Andover got record July rain and half the fields in town were underwater from the outside, not the inside. A field that’s drowned by groundwater looks exactly like a field that’s failed, and the fix for the first one is patience and a pump-out, not $25,000. We probe the field, look at the tank level, look at the weather record, and tell you which one you have.
Then, honestly, sometimes it’s the fifth thing: the field’s done. The biomat at the bottom of the trenches has sealed up after forty years and no amount of resting brings it back. We’ll say so. On a lot where a new field will fit inside the setbacks we’ll price a replacement straight. On a shoreline lot where it won’t, we’ll walk you through the options — a raised bed, an advanced treatment unit, sometimes an easement across the neighbor’s land — and be clear about which of those we do and which need a designer. Might cost us the job. That’s fine.
Most Andover repairs land between $400 and $2,500. A baffle or tee is the low end; a distribution box dug and reset sits around the middle; a line replacement with a locate and some digging is toward the top. We diagnose first, and the diagnosis comes with a written number for the fix before anything gets cut. If it turns out the field is done and you’re looking at a design and a state permit, we tell you that plainly and don’t bill you for a repair that wouldn’t have held.
It’s a symptom, not a verdict. A tank that refills to the outlet in a day is normal — that’s how a tank works. A tank that’s sitting above the outlet, with liquid backed up into the inlet pipe, means the field isn’t taking water. Why it isn’t taking water is the whole question. Could be a tilted d-box sending everything to one drowned line. Could be a crushed pipe. Could be groundwater after a wet stretch. Could be a sealed biomat after forty years. Three of those four are repairs. We open the d-box and probe the field before we say which.
An existing field can be repaired in place. The setback rules apply to new construction and replacement, not to fixing a d-box or a pipe on a system that’s already there. So if the trouble is something upstream of the field, we fix it and the field stays. If the field itself is finished, then yes — a new one has to meet the setback, and on a forty-foot lot that’s a design conversation, likely involving an advanced treatment unit or a different location on the lot. We’ll tell you which situation you’re in after we’ve looked, and we won’t pretend the second one is the first.
Maybe not. Andover’s wet summers — 2023 was the one people remember — push the water table up into fields that were built above it in a normal year. The field can’t drain into ground that’s already full. That looks like failure from the kitchen, but it’s weather. We pump the tank to take the load off, look at what the level does over a week or two, and if the field drains as the ground dries, you’re fine. If it doesn’t, we’re back to the list above. Either way, a pump-out is the right first move and it’s the cheap one.
We do the repair side and the installation side. A replacement system needs a design by a state-licensed designer and an approval from NHDES before anybody digs, and on a shoreland lot the design is the hard part. We work with designers who know these lots and we’ll get you to one. What we won’t do is sell you a design you don’t need — a good share of the “you need a new system” calls we get second opinions on turn out to be a d-box.
Same-week scheduling, straight prices, and a crew that knows the Lakes Region.
Tell us where the property is and what's going on. We'll get right back to you with a straight price.
We reply to every request within 2 business hours — emergencies first.
Lakes Region