Cleaning up after a flood

Flood water has the potential to cause adverse health effects if it is not dealt with immediately and properly. There is risk of exposure to contaminants like bacteria in the flood water, as well as potential exposure to electrical hazards, and the potential for mould growth.

After a flood, it is important to restore your home as soon as possible to protect your health and to prevent further damage to your house and belongings. Whether you do the work yourself or hire a contractor, the information below will help you organize the clean-up.

Immediate action is important. Your house and furnishings are less likely to grow mould if they are dried within 48 hours.

Before you begin

Set up a step-by-step action plan to:

  1. Remove all water, mud, and other debris.
  2. Dispose of contaminated household goods that cannot be easily cleaned and disinfected.
  3. Clean and disinfect salvageable items.
  4. Dry out your house and salvageable possessions as quickly as possible.

Be prepared to make difficult decisions about what to keep and what to throw out. Household items that have been contaminated by sewage, or that have been wet for a long time, should be discarded according to local regulations.

Assemble equipment and supplies:

Store valuable papers that have been damaged in an operating freezer until you have time to work on them.

First steps

  1. Remove standing water with pumps or pails, then with a wet/dry shop vacuum.
  2. Remove all soaked and dirty materials and debris, including wet insulation and drywall, residual mud and soil, furniture, appliances, clothing and bedding.
  3. Hose down any dirt sticking to walls and furnishings, then rinse several times, removing the remaining water with a wet/dry shop vacuum. Rinse, then clean all floors as quickly as possible. Flooring that has been deeply penetrated by flood water or sewage should be discarded.
  4. Work from the top down. Break out all ceilings and walls that have been soaked or have absorbed water. Remove materials at least 500 mm (20 inches) above the high-water line. Removing only the lower part of the wall applies if action is taken immediately after the flood or wetting event. Gypsum board walls that have been exposed to high humidity or standing water for a prolonged period of time should be removed entirely and thrown out. Ceiling tiles and panelling should be treated like drywall.
  5. Wash and wipe/scrub down all affected or flooded surfaces with unscented detergent and water. Rinse and repeat the process as needed. Concrete surfaces can be cleaned with a solution of TSP (tri-sodium phosphate) in water (one ½ cup TSP to one gallon of warm water). When using TSP, which is highly corrosive, wear gloves and eye protection.
  6. Bleach is NOT recommended. The presence of organic materials, the pH (acidity/alkalinity) of the water, the surface material and contact time affect the effectiveness of bleach for disinfection. Since these factors are not controlled in a flooding situation, bleach cannot be relied on for disinfection. Bleach fumes are harmful, but in addition, overusing bleach results in increased releases of chlorinated effluents, which can be harmful to the environment.
  7. Surfaces that are dry or have not been directly affected by flood water should be vacuumed with a HEPA vacuum cleaner. Further cleaning of concrete surfaces can be done with TSP. Washable surfaces can be washed with unscented detergent and water. Surface mould on wood can be removed with a vacuum-sander. Do not sand without simultaneous vacuuming. Wood that looks mouldy after sanding may need to be replaced.
  8. After cleaning the surfaces, ventilate or dehumidify the house until it is completely dry. Rapid drying is important to prevent mould growth. When the weather permits (low humidity and moderate temperature), open doors and windows and speed up the drying process with fans. If the weather is not suitable and drying is not happening fast enough, use dehumidifying equipment, consider renting extra units as necessary.
  9. To determine if the outdoor air can help dry the air inside, place a hygrometer (a tool that measures moisture in the atmosphere) in the area to be dried. Let it stabilize, then open a window and monitor the relative humidity (RH). If the RH reading goes down, that means the air is dry enough to assist the drying process. If the RH goes up, close the window.

What to keep or discard

Before moving back in


This item was last modified on June 24, 2015