[header] How to know if you need a dehumidifier [title] Identify signs of excessive ground water around your home. [step] Walk around your home and look for any signs that the water table is high. If you notice long-term standing water, see a water mark left on the outside of your home, or observe water marks in your basement, you may need a dehumidifier. 
[title] Search for water stains throughout your home. [step] Take the time to inspect your home every six months or year.