| Incorrectly installed systems can waste water and care must be taken not to contaminate mains water supplies through backflow. |
| If backflow occurs during blood sample aspiration or from a transfusion, there also could be contamination. |
| Other problems would be backflow into the system or a rising groundwater table that would allow seepage into the collection system. |
| Veins in the legs have valves which normally prevent any backflow of the blood on its way towards the heart. |
| A backflow protection device will be in place to prevent potentially contaminated water from entering the public water system. |
| Install a backflow valve to prevent sewer backup from coming into your home. |
