Planning
The Water Table Under Your Yard, and Why We Look First
Groundwater, a private well, a septic field, or a line somebody buried decades ago can each move a pool or change how its floor is built. None of them appear on a drawing. All of them are findable before anyone digs.
The short answer: yes, there is probably something under your yard that matters, and no, it usually does not stop you having a pool. What it does is decide where the pool sits, and occasionally how the bottom of it gets built. Both of those are cheap decisions while the pool is still paint on grass and expensive ones once a machine is running.
A pool excavation is not a shallow job. It goes well past the depth a patio or a footing works at, and well past where the ground freezes - which is why the question here is not how deep to build, but what is already down there at that depth. This is the one category of question a plan view genuinely cannot settle, and it is the reason a site visit is not a sales formality.
What is actually under a back yard?
Sorted by the only question that matters at planning stage: who knows it is there.
| What may be down there | Who knows, or marks it |
|---|---|
| Utility-owned gas, electric, water, telecom | Marked at no charge by the line owners, arranged through the state one-call system |
| Your own run to a garage, shed or yard light | You, an old drawing, or a private locating service you hire |
| Irrigation pipe and valve boxes | Whoever installed it, if any record survives |
| Roof and footing drainage lines | Frequently nobody, until they are found |
| A private well and its casing | Your well record, plus a physical locate on site |
| Septic tank, drainfield and reserve area | Kenosha County Planning and Development, from the parcel record |
| Seasonal groundwater | A test hole, read on the day and in the season |
| Old fill, buried debris, rock | Nothing reliably, which is why we probe rather than assume |
What the free locate covers, and where it stops
Wisconsin runs a one-call system, Diggers Hotline, which notifies the owners of buried facilities that someone intends to dig at your address. Those owners then send someone to paint and flag their own lines. There is no charge to a homeowner for it and it is not optional before excavation.
The boundary is ownership, not depth. A line belonging to a utility and crossing into public right-of-way is inside the system. One installed privately and living entirely on the property is outside it - no notification goes anywhere and nothing gets marked. Everything a previous owner ran to a detached garage, a pond pump or a hot tub pad falls into that second group, and a pool dig is deep and wide enough to introduce itself to all of it. Walk the yard with your builder and point at what you know about. That conversation finds more than any technology does.
A private well is its own protected zone
Plenty of properties outside the city here draw from a private well, and a well is not simply an obstacle to route around. Wisconsin protects private wells through the state well code administered by the Wisconsin DNR, and that protection includes separation between the well and what gets built near it.
We are deliberately not printing a distance on this page. The clearance that governs your build depends on your well, your parcel and the current rule, and the only version worth acting on is the one confirmed against your own property. What you can do now is useful and free: find the well record, get the casing physically located rather than estimated, and bring both to the design conversation. A pool laid out around a confirmed well position is straightforward. A pool laid out around a remembered one is a gamble.
A septic system has three footprints, not one
This is where good intentions most often go wrong, because owners picture the tank and forget the rest. A private onsite wastewater system occupies the tank, the drainfield that does the actual treating, and a reserve area - land held in hand so a replacement system can be built when the current one reaches the end of its life. That reserve area is not spare yard. It is part of the system, and building over it can leave a property without a legal path to a future septic system, which is a far more serious problem than a badly placed pool.
In this county the programme is administered by the Department of Planning and Development, and the county publishes what a sanitary permit and septic record covers. The separations that apply are set in state code and confirmed against your parcel, so treat any figure you read anywhere online as a starting point for a phone call rather than an answer. Ask the county what is on record for your address before you decide where the pool goes.
Groundwater, and why a liner pool cares about it
Here is the mechanism, without numbers attached. A pool full of water pushes down. Groundwater sitting in the soil around and beneath an empty or partly drained pool pushes back up. While the pool is full, those two roughly keep each other honest. The moment the pool is drained, whether for a liner change or by accident, the balance goes one way, and pressure under the floor is the force that matters.
That is why groundwater is a build-time subject and not a maintenance one. If the ground is wet, a builder designs for it: how the floor is made up, what drainage sits beneath and around the structure, and what relief detail is appropriate. Those choices are specified once the ground has actually been investigated on your lot. We will not describe a standard detail here, because there is not one - a wet parcel and a dry parcel get different pools, and the honest sequence is to look first and specify second.
The upshot is short. Groundwater rarely cancels a pool, it regularly changes one, and the worst way to discover it is on the day a liner comes out years later. The Wisconsin DNR publishes background on groundwater across the state if you want to understand what a builder is testing for.
Clay, fill and rock: what changes a dig
Soil is the quiet variable. Ground that holds water behaves differently from ground that drains, and both are workable once they are known about. Two conditions are worth raising at the consultation, because homeowners often hold the crucial information without realising it matters.
The first is old fill. If part of the yard was built up, levelled, or once had a structure, a pond or an older pool on it, say so - material that was placed rather than deposited naturally does not behave like the ground beside it. The second is rock. Boulders and buried debris are found rather than predicted, and that is the classic reason a below-grade quote carries a condition attached to it. A builder who explains that condition in advance is being straight with you. One who prices as though nothing can be down there is not.
Why this belongs in a site visit
Everything above grade can be drawn before anyone arrives - setbacks, dimensions, where the pool sits relative to the house. Below grade is a different kind of knowledge, gathered rather than drawn, which is why we look at a property before quoting rather than after.
Bring these to the visit and you will get a much better answer: your well record if you have one, your septic location and permit record if you have one, anything you or a previous owner buried, and the corner of the yard that stays soggy in spring. That last one is worth more than people think.
Find out what is under your yard before you design around it.
A free on-site consultation covers access, grading and what the ground is likely to be doing. See our pool installation page, or work through the Wisconsin Pool Planning Checklist before you talk to anyone.
The bottom line
Under most Kenosha County back yards there is something worth knowing about, and almost none of it is fatal to a pool. A well, a septic field and its reserve area, a private line nobody documented, water sitting closer to the surface than you would guess: each moves the pool or changes how its floor is built, and each is far cheaper to handle at layout stage than at excavation stage. Get the records, get the locate, name the soggy corner, and let the ground inform the design instead of interrupting it. Once that is settled, the build sequence and what the work does to the rest of the yard are the next two things to read, and the factors that move a real quote are on our pool cost page.