Signs of a plumbing leak causing dampness in the basement include water stains and wet spots on the ceiling in the basement. [3] X Trustworthy Source Energy Star Program run by the U. S. Environmental Protection Agency and Department of Energy focused on educating consumers about energy efficiency Go to source To inspect for leaks that you can’t see, check your water meter reading and don’t use any water in the house for 2 hours. Check the reading again after 2 hours. If there’s been a change, you have a leak somewhere that needs to be addressed. You may be able to address simple repairs yourself, such as changing a leaky washer, fixing a running toilet, or tightening a loose joint. For larger jobs, or if you don’t have much experience with plumbing maintenance, call in a professional to fix the leak.

You can also reduce steam by covering pots with lids when you cook, and by taking cooler showers and baths. If you don’t have exhaust fans, open windows when you shower or cook.

This is most likely a job that will require a professional, because you’ll have to cut into the frame of your house to install the vent. The job will likely cost around $200 USD. Inspect hoses and ducts regularly for cracks and holes that could be causing leaks, and replace the duct or hose if you find signs of wear and tear.

To make air in the house less dry, turn down the temperature of the furnace.

Empty the dehumidifier reservoir whenever it becomes full, typically once every 2 days. This will prevent spills and keep the appliance working well. Use a dehumidifying ventilator to extract the moist air and move it outside. [9] X Expert Source Victor BelavusAir Conditioning Specialist Expert Interview. 6 May 2020.

When the humidity level starts to rise, use the dehumidifier to control moisture while you address the cause.

When gutters become clogged, water builds up inside and drips over the edges. The water then collects around the base of your house, and may seep in through the foundation.

A sump pump system collects water from around the foundation of the house, drains it into a sump pit, and then pumps the water away from the house. In order to perform this task, the sump system has to be properly cleaned and maintained. Not all houses have sump pumps. If you’re not sure, check your basement for the sump pit, which is a large reservoir dug into the floor to collect water.

Typically, you can address a small crack in the foundation as long as it’s vertical. Call in a professional if the crack is horizontal, diagonal, or growing, or if you want it assessed by an expert. The foundation is the structure on which your house is built, so it’s always best to consult an expert if you’re unsure of a problem.

Look for masonry waterproof coatings like Xypex or Drylok.

Condensation forms when warm, humid air comes into contact with a cold surface, such as your basement wall or floor.

Only insulate exterior walls after addressing leaks and other areas where water is entering the basement from outside. Otherwise, you’ll trap water behind the insulation and end up with mold.