Water – Central A/C Draining Causing Stagnant Water – Dry Well

You'll want to create a small leach pit, which will allow the water to drain into the ground.

Start by digging a hole about 12-18" deep (depending on your soil), Next fill the bottom of the hole (about half the hole) with crushed stone (loosely compacted). Fill the rest of the hole to about 1" from the top with sand, then finish with a nice decorative stone. If the soil is typically very moist (i.e. you get a lot of rain), you can skip the sand and fill the hole all the way up with crushed stone, and then top with decorative stone. Another option would be to top the hole off with something like this

So you'll follow the same procedure as above, but rather than filling the second half of the hole with sand/stone you'll put in a drain pipe like this.

The whole idea here is to have the water leach into the ground, without forming a puddle where mosquitoes and other things can breed.

If you do this and still find that the water is pooling, you'll have to take more drastic steps. The best option from there would be to install a French Drain, and connect the drain line from the AC unit to it. There are already some questions that deal with french drains, so if it comes to that you should have no trouble finding out how to do it (how do i build a french drain).

You could also buy a small leach pit, but this might be overkill for your situation.

You'll bury this in the ground surrounded by 3/4" - 1 1/2" crushed stone, then connect the AC unit drain to the lower inlet pipe (the upper pipe is a vent). Before you drop it in the hole, remember to remove the small hole knockouts (to allow leaching). This will require a larger hole, and again may be over kill for your situation.

As others have suggested, a good excavator or even a landscape contractor might be able to find relatively simple ways to alter the landscape of your yard so that water will naturally flow away from the home.

Civil engineer would be your best bet but they are also expensive enough that I see them as the last ditch effort if other measures have been failing. Typically experienced landscape contractors or excavators can figure out where the water is flowing during a rainstorm and divert it away from the house with a bit of digging.

French Drains

While water may not be seeping into your foundation right now, having all of that water pool next to the house is inviting problems. Reagrdless of landscaping, it is a good idea to install french drains around the perimeter of your house if you know that rain water is inevitably flowing towards your home.

The following image is a typical installation. The drain itself is typically a trench running a couple of feet typically from the house and going down below the frost line. You want the drain pipe to be deep enough that it will be below the frost line so that water flowing inside the pipe will not freeze and crack it. The frost line differs by region, obviously colder climates have a deeper frost line.

The holes allow water to flow down or up into the pipe, while the pipe running at a slight downward slope will take the water and flow it away from the house in another direction. It typically sits on a thin bed of gravel and the trench is filled with gravel rather than soil as water will more easily flow down through to the drain pipe if the trench is filled with gravel rather than soil. Soil will also potentially clog the drain making it ineffective. For aesthetic reasons, sod can be placed over top or you can do something clever like make a rock garden.

If you are a masochist and thoroughly enjoy pain, then you can grab a shovel and dig the trench, but for those of us who are lazy and like excuses to play with complicated equipment, you can rent a backhoe for a day and turn a week long digging job into a 2 hour weekend job. When digging however, be extremely careful about the location of underground utilities:

• Water lines

• Gas lines

• Sewer lines

• Electrical conduit

• Cable and telephone lines.

Make sure to identify where these come into the house and approximate their location and depth in relation to where you intend to dig your trench. If any of them are close then it is probably best to call a professional just to be safe.

Gutters and Downspouts

Another possiblity could simply be that your gutter downspouts are draining too close to the house, or are draining into storm drains that have become clogged.

The following is an example of a downspout draining too close to the foundation.

Many times this can be fixed rather easily, by extending the downspout horizontally away from the house, or channelling it far enough away that it has somewhere to flow other than down your foundation walls. Check out your local hardware store because there is a number of ways to effectively and cheaply handle this.

Also it is a good idea to check your gutters regularly for clogs. A clog can prevent water from flowing from your gutters to your downspouts, causing it to pour over the edge or sometimes down the side of the house. This is also something to check for.

Downspouts can also sometimes flow into an underground drain, which can sometimes be the source of the problem. This drain typically will be a storm drain that flows away from the house or to a public storm drain. These can sometimes become clogged causing water to not flow properly away from the house. Most landscape contractors can easily help unclog such drains if you suspect that this might be the case.

This should give you some ideas of things to look into or try before contacting a civil engineer, as the fix might be more manageable and less complicated than you think. And as far as a sinkhole swallowing your house, I have only ever heard of that happening because of a house sitting on top of a collapsed coal mine. If you live in a heavily mined area then your municipality probably has maps that will show whether your house sits overtop of an old mine. I wouldn't personally worry about this. The cracks in your foundation might be from the ground settling or moving slightly from excessive soil saturation.