We moved into our home nine months ago, and slowly the situation of runoff from other properties has led to a condition where the back yard is very marshy-like (your shoes would get muddy and it's a little stinky), up to 36-48 hours after the last rain. With rain every two to five days, I'm concerned with having great conditions for mosquito beds, not to mention damage to my homes foundation.
The marshy-like areas are directly against the house in the back that stretches half the foundation, along with the side of the house for a half the house, but isn't necessarily against the foundation. We had asked the drainage issue before taking ownership, but was told it wouldn't be an issue and it was designed to drain properly.
Anyway, this leads to my question. My home warranty/builder has told me they will do: "a light sanding of the area" and that "with the nearly daily rains the area is receiving patience is the key as we are unable to obtain the best results with the soggy conditions. Once this is completed you will be responsible for any further maintenance and corrections in the future." Will this help fix the issue? How much sand should I expect to need to put down?
Best Answer
I would not expect that a layer of surface sand will help the problem, you will just have sandier mush. If you're getting runoff from surrounding properties, more water is coming in than the ground can handle.
If your lot has some grade and the side away from your neighbors is lower, it might help to install a perimeter drain around the lot to capture runoff from your neighbors and redirect it so that it doesn't enter your yard.
Your comment on the question indicates that there is a lot of surface water that flows over the property, so that suggests that some combination of a perimeter drain and contouring the perimeter of the lot should help.
But there are limits to how effective this can be. Some of your neighbors' runoff will soak into the ground on the way. The area soil and grading can create a high water table and your lot, being lower, may be at the water table level when it is high. I had this situation at a prior house. If that's the case, a perimeter drain won't totally solve the issue because at least some of the problem water is already below any practical drain system you could install.
Another or supplemental approach is to plant one or more "wet soil" trees in the yard. These are trees that thrive in very wet soil. Weeping willow trees are often used for this purpose. They can soak up water like a sponge and solve the problem of a marshy yard. This link lists a variety of trees that thrive in wet soil and can be used for this purpose.
Given your description of the amount of surface water flowing over your lot, I would start with a perimeter treatment (contouring and/or drain) to divert the runoff. See how far that goes in solving the problem. If the soil is still too wet, consider adding the tree solution.