Most people never think about where their septic system is until they need to. Then they go looking for the paperwork – the approved plan on file with the county, the sketch the last owner left in a kitchen drawer – and they dig where it says to dig. Sometimes the system is right there. A surprising amount of the time around here, it is not.
We were on a septic repair in Red Hook this month, digging test holes while the engineer and the Dutchess County Health Department witnessed soil testing. Opening the ground on an older property is usually the first time in decades that anybody gets a real look at what is actually down there, and that is worth understanding before you plan anything around it.
Why the file is wrong so often
There is rarely anything sinister behind it. A lot of the systems in Dutchess and Columbia County went in decades ago, some of them before the county was keeping the kind of records it keeps now. A plan gets drawn, the approval comes through, and then something on the day of the install makes the crew move. Ledge in the way. A wet spot nobody expected. A tree worth saving. The system goes in ten or twenty feet from where the drawing shows it, the job gets covered, and the drawing stays in the file exactly as it was.
Then add fifty years of the property changing. Additions, a new driveway, a pool, a shed, a fence line moved, landscaping grown in over everything. Even when the original plan was right, the landmarks it referenced may not exist anymore.
Why it matters before you dig
A septic system is not a thing you want to find by accident. A drain field is shallow, and the pipe and stone in it are fragile compared to a machine bucket or a set of tracks. We have seen fields crushed by equipment parked on them and lines broken by a footing dug where the plan said there was nothing.
It also decides what you can build. Setbacks from the tank and the field affect where an addition can go, where a pool can go, where a new well can go, and how close a driveway can run. If the system is not where the record says it is, every one of those measurements is being taken off the wrong spot. That is the kind of thing that turns up late, after the concrete is poured, and it is expensive to unwind.
And it comes up on a sale. A buyer’s inspector works from the record too. Finding out at the table that the field is not where the file says it is has stalled more than one closing.
How the system actually gets found
Usually it is a combination of things. You start with whatever record exists, because even a wrong plan tells you the general idea – how many chambers the tank had, whether it fed a drain field or a drywell, roughly which side of the house it served. You follow the line out from the house, because the pipe leaving the building points where the tank went. You read the ground: a strip that greens up faster, a strip that stays wet, settling over a trench. Then you dig carefully, by hand near anything you expect to hit.
On the Red Hook job we were already opening the ground for the deep and percolation tests the engineer needed, so that looking came out of work that had to happen anyway. That system has since been replaced – here is what the leach field replacement involved. That is not always how it goes. Sometimes locating a system is its own afternoon with a machine and a shovel.
The as-built is how this stops repeating
Dutchess County has a fix for this going forward, and it is worth knowing the name of it. When an existing single-family system is repaired or replaced in kind, the work is registered with the county in two steps: a SAN-36A filed before the work as the notice of intent, and a SAN-36B filed after it is finished as the as-built, confirming what went in and exactly where it sits. That second form is the whole point. It puts the real location in the file instead of the intended one.
Your engineer or designer files those, the same way they handle the design side. Our part is the excavation – digging the test holes when the engineer and the inspector are on site, and doing the install once the design is approved. But if you are having work done on your system, it is worth asking whoever is filing that the as-built reflects what is actually in the ground, because the next owner, or you in fifteen years, will be reading it.
If you do not know where yours is
Start with the county. Dutchess County keeps records on file and will pull what exists for a property. Your town building department sometimes has a copy too, and if the house has changed hands recently the old closing file may have one. Treat whatever you get as a starting point rather than a map – it tells you what was approved, not always what was built.
If you are planning an addition, a pool, a driveway or anything else that puts weight or a shovel in the back yard, it is cheaper to know before than to find out during. We work in Red Hook, Rhinebeck, Pine Plains, Millbrook, Stanfordville, Hudson and the towns around them, and we are happy to talk it through.