What kind of grass do you have? In Iowa I'm guessing fescue and/or Kentucky bluegrass.

Was the soil ever rototiled? If so, how long ago?

Search this forum or Google for "lawn leveling bermuda". Yes it is not about fescue or KBG but you will get some ideas.

dchall thanks for the information. My lawn is from new home construction in the fall of 2011. I believe the cheap crew used to lay the sod just leveled the soil and layed the sod over top. The grass is 50/50 KBG and perennial rye. Is the sand that people speak of using for leveling also called mansand (this is paver sand that landscapers up here use). Also, for deep settled spots should mixture of sand and soil be used? IS there any issue with overseeding and getting grass to germinate after using sand to level?

The only problem with using topsoil for leveling is that it clods up. If you have a 1-inch diameter clod, then you have a 1-inch deep groove in the leveled surface where the clod was dragged along by the drag. Breaking clods to make fine topsoil takes forever. If you want to fill in known holes with topsoil, that's fine. Crush any clods and dust that stuff in 1/4 to 1/2 inch per week until you have it up to level. If that is your only problem, you might not need to go to the trouble of leveling the entire lawn.

The best sand is anything NOT from a river bottom. River sand is rolled and round particles. These round particles never solidify into a surface. Fresh sand is chipped and not rounded yet. It will lock into itself. You can see it with a magnifying glass. It is not a deal breaker if all you can get is rounded particles. This might be more of a theoretical difference than a practical one.

No issues with seeding into sand.

My problem with the previous leveling threads is it was always bermuda. Seems to me the same approach works for the northern grasses. Scalping it is my concern. The lower you can mow the less sand you will use to achieve a level surface. Hmmmmm. Anyone else have any thoughts on scalping KBG and rye to level it?

I've got KBG and have been leveling low spots for the past couple of years. Mason's (Sharp) sand works best, but I've also used play sand when I was too lazy to find good Mason sand.
I cut the area to a height of 2". I wouldn't advise scalping. Apply up to 1/2" total sand thickness 1/4" at a time. After each 1/4", use a leaf rake to work the sand down and pull the grass blades up through the sand. Water. Repeat the process after a couple of weeks until level.
Over seeding Mason's sand works well. If you use play sand (which I don't advise - the grains are rounded like river sand, it's more expensive and may contain chemicals) the seed does not seem to germinate well. Probably due to the chemicals used to clean it. This process works well for smaller areas (12 sq ft or so) as it is a lot of manual labour.

Grass1950, What approach do you recommend with KBG on spots that are depressed more than a 1/2"? I have a couple spots that might be 6" or more inches deep.

I have had success cutting the sod from the surface, leveling (raising or lowering) and replace the son on the new level surfaces.

I have found that when you do this with in weeks you can not tell where you made the adjustments.

Like all recently lay sod or grass you have to keep it watered until it is reestablished.

My areas are/were only a couple of inches low. Just rinse and repeat the process every month or so for a couple of years. If you are talking a large low area (say 10x10) or if you are in a hurry, then I would probably try to remove and re-lay the sod after using sand to level under the sod. I fear your problem is going to be that unless your grass is thick and mostly KBG, it wont cut well into sod. Rye is not known for knitting together and if the sod breaks into small chunks you are going to have a mess trying to re-lay it.
The closest I have done is repair a 100' washout/ditch in my yard. It was 6-8" deep and 1 1/2' wide in areas. I mixed sand and top soil (and used peat moss when I ran out of top soil) to add some organic mater at a ratio of 8 sand to 2 soil or peat moss in a wheel barrow. I like sand because it is is easy to level and settles very little. Then I seeded the area--still the best grass in my lawn. Good Luck.

This post was edited by grass1950 on Sun, Apr 14, 13 at 20:31