Q: Last week we covered the surveyor, market-driven lot sizing, TIF financing, and the phasing decision for a 30-acre subdivision near a supply-constrained Midwest city on one of the Great Lakes. Today we walk through the approvals process itself: stormwater, the sewer and water decision, and what the town board is actually looking for.
A: Your surveyor has assessed the parcel, you know your lot count, and you have decided how to phase construction. Now the approvals machinery starts turning, and three questions determine how smoothly it goes.
Stormwater comes first, and it comes early.
The Wisconsin DNR requires a stormwater management plan before a subdivision plat can be approved in most jurisdictions, and this is not a formality. Impervious surfaces, meaning roads, driveways, and rooftops, change how water moves across your parcel and onto neighboring land. Your engineer will design detention ponds, grading, and drainage easements to keep post-development runoff at or below pre-development levels. Skip this step or underestimate it, and you will be redesigning streets you already platted. Your surveyor’s engineering firm connections matter again here. A firm that has handled DNR stormwater permits in your municipality before knows what the reviewer will flag before the reviewer flags it.
The sewer and water decision.
Every lot needs both, and in Wisconsin, you may not actually have a choice: once municipal sewer and water reach a lot, most municipalities require connection by ordinance, and property owners who don’t comply can be connected by the municipality with the cost billed back as a special assessment. Where municipal service does not reach your parcel, or a municipality doesn’t require connection, you are looking at private wells and septic systems, and this is where many landowners underestimate both cost and complexity.
There are three general septic system types in Wisconsin: conventional gravity systems, mound systems for parcels with high water tables or poor soil, and holding tanks, used rarely and only where nothing else works. A state-licensed technician determines which type a given lot needs through a percolation test, which measures how well the soil absorbs effluent. Soil testing happens lot by lot, not once for the whole subdivision. A parcel that looks uniform on a survey map can have wildly different soil conditions from one end to the other, so budget for individual perc tests as part of your due diligence, not as an afterthought once lots are under contract. One developer’s real-time account of losing his ideal building site to a septic setback arc, even on land with zero zoning restrictions, shows how easily this catches an otherwise careful buyer off guard. Keep in mind that perc test results can shift between the time you plat a lot and the time a buyer actually applies for a septic permit, so a result from early in the project should not be treated as permanent.
Wells follow a similar logic. A drilled well with casing is the more dependable option, reaching deeper into the aquifer and carrying less contamination risk than a shallow sand-point well. Most states also require minimum separation, often 50 to 100 feet, between a well and any septic system, which is one more reason lot layout should account for both systems together rather than treating water and waste as separate design problems.
Once a lot sells, ongoing septic maintenance becomes the buyer’s responsibility, not yours. Still, disclose the system type, the pumping schedule if one exists, and any perc test results clearly at the point of sale. A well-documented lot moves faster and invites fewer questions at closing than one where the buyer is left to guess.
What the town board actually looks at.
Board members are not engineers. They are looking for confidence: a complete plat, a stormwater plan already cleared by state or local reviewers, and clear answers on sewer and water. What counts as “clear answers” varies. Some states move fast on these approvals, others slow, and requirements differ from one municipality to the next even within the same state. Learn your own board’s expectations and timeline early, rather than assuming what worked in a neighboring county will hold here. Boards also want to know your subdivision will not become their problem if something goes wrong midway through construction. That is where bonding comes in.
Bonding requirements for phased development.
Most municipalities require a performance bond covering the infrastructure costs for whatever phase you are building. If you chose the 5 to 10 acre first phase from last week’s column, your bond covers that phase only, which keeps your upfront capital exposure down alongside your construction costs. If you chose full buildout, expect a bond sized to match. The bond guarantees the municipality can finish your streets and utilities if you cannot. Talk to your municipal administrator about bonding requirements before you finalize your phasing decision, not after, since the two numbers are connected.
The professionals you actually need.
By this stage you likely have a surveyor, a civil engineer, and possibly a stormwater consultant. Resist the urge to add professionals for credentials alone. A large regional engineering firm with an impressive résumé but no history in your specific municipality will move slower and cost more than a smaller local firm the town board already trusts. Local experience with your particular reviewers is worth more than a longer client list.
Next week, the finale: the one mistake that kills more subdivision projects than any other, and how to avoid it before you break ground.
