Septic and well: the two records that are hardest to get and matter most

Outside the sewered parts of Grand Rapids, Holland, Muskegon and their immediate suburbs, most West Michigan property is on a private well and an on-site septic system. Neither is visible, both are expensive to replace, and the paper trail on both sits with the county health department rather than with the assessor, which is why they are the two records most often skipped.

Michigan is the only state in the country with no statewide sanitary code for on-site sewage. Rules are set county by county, which means the answer to almost every question in this article changes when you cross a county line.

• The year the system was permitted, which is the best available proxy for its age. A conventional system installed in 1978 is at or past the end of its design life.
• The design: tank size, field type, and, critically, the number of bedrooms it was sized for. A three-bedroom field under a house where somebody has since finished a fourth bedroom in the basement is a real and very common problem, and it becomes the buyer's problem at the point of failure.
• The soil evaluation and percolation results from the original installation, which say something about how the ground drains.
• Repairs and replacements, where they were permitted. Work done without a permit leaves no trace here at all.
• For wells: total depth, casing depth and material, static water level, the aquifer tapped, and the driller's log.

What it does not show is condition. A permit record is a birth certificate, not a physical. A 1995 system that has been pumped every three years may have another decade in it; a 2015 system that has taken twenty years of laundry from a family of six may not.

Some Michigan counties require an on-site evaluation of the well and septic before a property transfers, and some do not. Where the requirement exists it is enforced at the county level, it applies to the transaction rather than to the property, and it has a defined validity period.

This is a rule that changes, and it changes without anybody in the transaction being told. The health department is the authority, and it is worth one phone call rather than an assumption: the difference between a mandatory inspection and a negotiated one determines who pays for the failure it finds.

Where an evaluation is not required, ask for one anyway and make it a contingency. A septic inspection is a few hundred dollars. A replacement field on a difficult lot is tens of thousands, and on a lot with poor soils, a high water table or not enough room for a conforming field, the number can be much worse, because the alternative is an engineered system.

At minimum, coliform bacteria and nitrates. Bacteria indicate a compromised well: a bad seal, a failed cap, surface water reaching the casing. Nitrates indicate agricultural or septic influence, and matter especially where there is or may be an infant in the house.

Then arsenic. Parts of the Michigan bedrock, the Marshall Formation in particular, which underlies a swathe of the state, release arsenic into groundwater naturally, at levels above the federal drinking water standard in a meaningful fraction of wells. It has no taste, no smell, and no visible effect. It is a specific test and it is not included in a standard panel unless you ask.

Depending on the location, it can also be worth testing for iron and manganese, hardness, and, near a known contamination site, an airport or a former industrial parcel, PFAS. Michigan has been more aggressive than most states in mapping PFAS sites, and EGLE's inventory is public.

County codes set minimum separation distances between a well and a septic field, between a septic field and surface water, and between a field and a property line. On a small lakefront lot these distances are frequently the binding constraint on whether a failed system can be replaced at all in its current location.

That is the question to ask about any older cottage on a small lake lot: not whether the septic works, but where the replacement would go if it stopped. Sometimes the honest answer is that there is nowhere, and the fix is a holding tank with a pumping contract, which is a very different cost of ownership.

Health department permit records are not published as live map layers in most West Michigan counties, so this is one of the checks the lookup will tell you to make rather than make for you.

What it does give you is the ground truth around it: the USDA soil survey's own rating of the parcel for septic absorption fields, where "very limited" is a finding worth having before an offer, the depth to the seasonal high water table, and the EGLE Wellogic records for wells within half a mile, which tell you what depths drillers are actually hitting in that neighbourhood and roughly what a new well would cost.

Saying plainly which checks the tool cannot make is the point rather than an apology. A report that quietly omits what it could not reach reads exactly like one where everything came back clean, and on a septic field that difference is somebody's money.