Most of the worst mistakes you can make with your home all have one thing in common: water. Whether the water is from rain or your own plumbing system, the damages can be costly to repair.

Specifically, watch your foundation and the wood in your walls and floors. They're the first to go up when a house is built and the first to break down once water gets in.

Even seemingly harmless things, like adding a sunscreen to your deck or a fence around your house, can allow water to sneak in, according to the Homeowners Education Association. Before you go tearing down your fence, however, there are bigger mistakes you may be guilty of.

Watering the Foundation
You probably know not to water your foundation like your lawn, but your downspouts and irrigation systems may not. The Homeowners Education Association says one of the biggest mistakes homeowners make is letting their irrigation sprinklers spray the house.

“People don’t realize water has to be carried away from the foundation of a house,” said Lawrence Pevec, owner of Hanz-On Pro in Boulder, Colorado.

If your house has gutters, ensure that the open ends of the downspouts are pointed away from the house. Water funneled toward your foundation can cause the soil to expand and put pressure on the foundation walls -- especially if the ground around your house consists largely of clay. If that happens, it can crack your foundation, costing $8,000 or more to fix. The odds of cracking are even higher if you have a basement.

“A foundation is one of the things you want to be careful with because it can cause lots of expensive problems,” Pevec said.

Sprinkler water may not be enough to damage your foundation if you only water once a week, but it can rot your walls.

Ignoring Your Doors
Exterior doors do not repel water as well as you may think, according to both Pevec and the Homeowners Education Association. If you regularly clean your outside doors with a hose or power washer, you may be inviting dry rot.

Even if you don’t use a hose on your doors, rainwater can come in if the caulking has shrunk or cracked, according to Pevec. Water that seeps under the door can warp your wood or tile floors or cause mildew in your carpet.

Beyond the potential structural damage from your leaky doors, you must be vigilant against mold. If you are sick all winter, Pevec says, it could be from mold.

The Homeowners Education Association advises using only a dusting brush or damp towel to clean your doors. Check the caulk around your doors once a season to keep moisture out of your walls.

DIY Plumbing
Attempting home maintenance yourself can save you money, but more often than not it leads to disaster. A botched plumbing job can flood your house with water or -- worse -- with sewage.

According to the Daily Mail, even installing a new washing machine should be left to the pros. When homeowners connect their washers to surface water drains instead of the waste pipes, it could send dirty water and detergents into local streams.

If you decide to go ahead with a plumbing job, Pevec says, familiarize yourself with the location of your water shut-off valve. Shut-off valves can be hidden, but usually they are in your basement, crawlspace or utility room.

If your DIY project goes wrong and water starts flooding your house, head to the shut-off valve. By turning the lever 90 degrees, you can save thousands of dollars of repair, according to Pevec.

Not Cleaning Your Gutters
It may be a pain to get the ladder out, but putting off cleaning your gutters for more than a year can lead to bigger problems than clumps of leaves. Gutters that don’t drain correctly can funnel water onto your roof, walls and foundation.

Water that makes its way past your gutter system can start rotting your walls while staying hidden behind drywall. You may not see the problem on the inside until thousands of dollars of damage has already been done.

Clean your gutters at least annually. If you live in an area with lots of trees, check them two or three times a year.

If ladders aren’t your thing, it is worth spending a few hundred dollars to hire a company to clean your gutters. Otherwise, you could be looking at a $1,500 to $3,000 bill to replace your gutters and even more to fix the problems they caused.

While you are up there cleaning the gutters, make sure chunks aren’t missing or pulling away from the house. The additional weight from snow or ice in the winter can misshape your gutters, changing the drainage path.

Laying Tile
Because the replacement of a tile floor is often driven by a desire for a visual change, you might not consider a less-than-perfect installation a maintenance mistake. There is more at stake, however, than mere cosmetics, according to Lawrence Pevec, owner of Hanz-On Pro in Boulder, Colorado.

The most common places for tile floors are bathrooms and kitchens. Because of high levels of moisture -- especially in bathrooms -- faulty tile floors can result in rot in the underlying structure.

To protect your floors, check your grout regularly for cracks. If it cracks again soon after you fix it, you may have a bigger problem.

“People wonder why the grout in their tile cracks, but often it is because there is nothing between the grout and subfloor,” Pevec said, noting that this is especially true for houses built in the 1960s and 1970s.

Pevec also warns against laying tile over linoleum or other existing flooring.