Michigan ground snow loads by county, and what they mean for a roof

What the table is

Michigan amends the residential code with its own tables of local design values, and Table R301.2(5) is the one that lists ground snow load by county. The number is in pounds per square foot (psf) and it describes snow lying on the ground, not on a roof. It is a design input for the code, and nothing in it is addressed to a homeowner choosing shingles.

On which code applies: as of Oct 19, 2026 LARA still lists the 2015 Michigan Residential Code, and a court order stopped the 2021 replacement from taking effect on August 29, 2025. That may change, so check LARA before you rely on any table in this guide. The county values below are the ones in the table as we read it, and a township or city can be set apart from its county, as the exceptions column shows.

The counties we recorded

County	Ground snow load (psf)	Exceptions the table lists
Wayne	20	Northville 25
Oakland	25	None recorded
Macomb	25	None recorded
Washtenaw	25	Ann Arbor, Ypsilanti and Saline 20
Genesee	30	Davison, Fenton, Grand Blanc and Linden 25
Kent	35	None recorded
Ingham	25	Lansing and East Lansing 30
Kalamazoo	30	Parchment, Alamo, Cooper and Oshtemo townships 35
Calhoun	25	Battle Creek 30
Saginaw	35	None recorded
Midland	35	None recorded
St. Clair	25	None recorded
Lenawee	20	None recorded
Marquette	70	None recorded
Houghton	80	None recorded
Keweenaw	90 to 100	None recorded

This is a selection, not the full table: the code lists every county, and Monroe and Hillsdale also sit at 20. Statewide the table runs from 20 to 100, which is the most useful thing to take from it. A house in Lenawee County and a house in Keweenaw County are designed for very different snow on the ground, and a house on the Grand Rapids side of the state (Grand Rapids is in Kent County, at 35) is not designed like one in Ann Arbor at 20.

If your township is not in the table above, do not guess from the nearest row. The table lists exceptions inside counties, so a neighboring township can differ. Ask the building department, which is local in the cities LARA’s Statewide Jurisdiction List shows as local for building, including Grand Rapids, Ann Arbor, Lansing, Kalamazoo, Saginaw, Midland and Portage.

Ground load and roof load are different numbers

The table gives ground snow load. The load on a roof is derived from it by the designer, and that derivation is engineering. We will not do it here, and we found no Michigan rule that lets a homeowner convert the table to a roof number by multiplying. If someone gives you a “roof snow load” for your house, ask what ground figure and what method they used.

What it means for a flat roof

We found no Michigan rule setting a number for flat roof replacement. If you are replacing a membrane on a roof that has ponded water or sagging, that is a conversation for a roofing company and, where framing may be involved, for the building department. Our page on flat roofs covers the systems, and the how long a roof lasts guide gives the one lifespan chart we found, with its caveats.

What it means for a roof replacement quote

For a typical shingle replacement, the snow load table does not change the scope of work on its own. What Michigan’s code does require on a replacement is spelled out elsewhere: roof replacement includes removing existing layers down to the deck, and Michigan’s amended Table R301.2(1) says an ice barrier underlayment is required, and the base code text runs the barrier from the eave edge to at least 24 inches inside the exterior wall line, with a longer run on slopes of 8:12 or steeper. We found no Michigan amendment to that text, but confirm it with your building department. Our ice dam and ice barrier guide explains why that is an eave strip and not the whole roof.

If a quote refers to snow load, ask what it is for. A contractor may be pointing to a structural repair, a decision about framing, or simply repeating a number. Ask in writing, and the department that issues the permit can say whether the snow load table is relevant. The permit guide lists what several cities say about re-roofs.

Reading the exceptions

Two counties show how the exceptions work. Ingham County is 25, yet Lansing and East Lansing are 30, so two homes a few miles apart can sit under different design figures. Kalamazoo County is 30, and four townships (Parchment, Alamo, Cooper and Oshtemo) are 35, which is the same figure the table gives Kent County. The pattern repeats in Genesee County, where Davison, Fenton, Grand Blanc and Linden are 25 inside a county figure of 30. When you call, give the building department your street address and ask which row of Table R301.2(5) applies to it, because the county name alone can send you to the wrong line.

What the table does not tell you

It does not say how much snow your roof is carrying today or after a storm, and it does not say whether a given roof is sound. We found no source that links these figures to roof lifespan. Do not climb up to measure. OSHA says falls are the leading cause of death in construction, and snow on a pitched roof is no place to learn that.

The table is good for a quick check on your area’s design assumptions, and for a number to bring up when you ask the building department what applies to your address. Write down the county, the city or township and the figure you were given, and the date you asked.