Hillside homes on the bluffs

The bluffs that give the city its name are loess: deep, wind-blown silt. NRCS describes soils like Monona as very deep, well-drained loess soils on loess hills and side slopes.^1,2

Why hillside foundations move

Loess drains well but erodes easily when water runs across it, and fill on graded hillside lots can settle. Common trouble spots include downspouts that empty onto a slope, retaining walls that are failing, and the downhill corner of a house settling.

What helps

• Pipe downspouts to a stable outlet so they don't empty onto bare slopes
• Keep vegetation on slopes, and fix erosion early
• Have a pro check retaining walls, since a failing wall can undermine the house
• If a corner is settling, ask about piers, and get an engineer's opinion first