You can reduce the amount of water entering your property by using sandbags, plywood or metal sheeting placed on the outside of doors, window frames and airbricks. Even if you cannot create a complete seal, this will reduce the amount of floodwater entering.
If you have silicone sealant to hand this will help to make doors and windows more resistant to floodwater. Open the door or window and place the sealant around the frame, then close and lock the door until the flood has passed. Do not permanently seal any airbricks, wall vents, or air intakes/vents for appliances such as boilers. These will need to be re-opened as soon as possible after the flood and permanently blocking them may be hazardous.
Floodwater can enter through drains, toilets and other outlets such as washing machines. The simplest way to prevent this is by putting plugs into sinks and baths and weighing them down with a sandbag or other heavy object. Outlets from washing machines and dishwashers should be disconnected. Place a sandbag in the toilet bowl and block the washing machine drain with a suitable plug (e.g. cloth or towel) to prevent backflow.
Floodwater can contaminate foodstuffs and chemicals such as paints, garden pesticides and household cleaning products. Similarly they may spill or leak into the floodwater causing additional cleaning-up problems. Store any materials like this in the upper part of your home, garage or garden shed.
(China.org.cn September 12, 2008)