IMPORTANT! - Water in the basement can be very dangerous.

  1. Do not go into a basement with standing water. Electricity + Water = Danger.

  2. Call your municipal public works department to report the problem. If your municipality is unable to help you, call MMSD at (414) 272-5100.
  3. Call your homeowners/renters insurance agent.
  4. Wait for the water to drain out of the basement before entering. Or, call a qualified electrician to disconnect the power before you enter a flooded basement.

Why is There Water in My Basement and How Did it Get There?

There are many ways water can enter your basement. Often reducing or eliminating the water is within the grasp of most homeowners.  The following content will guide you in assessing where the water may be entering your basement and what you can do to minimize this risk.

Troubleshooting Water in Your Basement:

  • Cracks in the foundation wall, floor, or where the basement wall meets the floor
  • Floor drain or plumbing fixtures (toilets, sinks, showers)
  • Door or windows
  • Roof penetrations (chimneys, plumbing vents, electrical service)

Water From Cracks in the Foundation Wall, Floor and/or Where the Basement Wall Meets the Floor

The best time to troubleshoot basement water problems is when it is raining. Grab your umbrella or rain jacket and walk around the outside of your house to take note where water is pooling and which direction water is running.  You most likely will find the location of the water entering your basement to be directly related to misguided water on the perimeter of your house.

  • Most commonly this water is the result of water pooling near the foundation from grading that is sloped towards the foundation. Broken or clogged rain gutters and downspouts without extensions make this much worse.
  • During extended periods of wet weather and during the spring snowmelt and thaw, seepage can be due to naturally high groundwater which simply means the soil around your basement walls can’t hold more water. Water pooling outside on the surface near the foundation makes this condition worse. Try to move snow and ice that blocks a free path for water to run away from the house.
  • If you have a sump pump, water should be entering the pump basin if you have seepage in the basement. If water is not running into the basin, you may have clogged foundation drains. This will require a plumber to assess. Occasional minor seepage is typical. While it can be a nuisance, it is fairly harmless. Regular seepage and/or flow through the basement walls cause significant damage to the house foundation over time.
  • When tackling water seepage:
    • The source of the water should always be found and redirected away from the outside of the house prior to any cosmetic patching or refinishing of internal basement walls.
    • Any waterproofing, crack repair, or foundation repair needs to be done from the outside on the exterior of the basement wall. While this is usually a big task involving digging, trying to block water on the interior of the wall traps the water in the foundation wall and causes serious damage over time.
water flooding in a basement

Water From a Floor Drain or Plumbing Fixture

A backup from the floor drain or an overflowing plumbing fixture is always a sign that the sanitary lateral is partially or fully blocked.  The blockage may be a physical blockage such as roots, grease, tangled items such as wet wipes, or the worst case, a pipe collapse. The “blockage” may also be water backing up from the public sewer that is not letting your water run out. There are a few key questions to help figure it out:

  • Is it raining, or has it been raining?
    • If the weather has been dry and you are using water in the house especially high flow uses such as a shower or laundry, most likely your lateral is blocked.  The water backing up is most likely your own water. Stop using all water immediately and call a plumber.
    • If it is raining, if possible, see if your neighbors are having basement backups. If your neighbors are having backups at the same time you are, the public sewer is likely full and backing water into your basement through your sanitary lateral. Call your city or village and submit a wet basement form.
    • If your neighbors are not having backups, your lateral is likely blocked. The backup is more likely to happen when it is raining because groundwater leaks into the lateral filling it faster than water can run out. Stop using all water, if you have connected foundation drains. However, even if you stop using all water, the water backup can continue to get worse until the rain stops. Contact a plumber. 

MMSD has financial incentives available to homeowners to replace their sewer lateral. Visit the Pipe Check Program to learn more!

Water From Doors or Windows

Generally, water will be observed on or around the window sill or door sill. Potential Reason(s):

  • Grading plays a major role in where the water ends up on your property.  When looking at the grading you should be looking at all areas around your house including the landscaping directly surrounding the house, paved areas, the lawn, and gardens. Your goal is to have all water that falls on your house roof and across your entire property to run away from the house.
  • Seals or caulking is failing
  • Faulty gutters and/or downspouts 
  • Clogged yard or area drain

NOTE: A door or window should not be expected to hold back pooling water.  Once underlying issues such as grading, gutters, and downspouts are corrected, replace or repair damaged doors, windows, and caulking to prevent rainfall from seeping in.

Water From Penetrations

If you have clear water that pools in the basement that doesn’t appear to be coming from the walls or a plumbing fitting, look overhead for water dripping or running from a leaking plumbing fixture from the upper level.  Look for water running down the sanitary stack, chimney, or electrical service conduit (during a rainfall) from a leaking roof penetration.