The penetration of polluted water to the drinking water system can cause harm to humans and animals. The quality of the water is tested in the water sources and in the supply network regularly. Nevertheless, the quality of the water in the supply network might diminish due to a number of reasons:
- Use of the water system to deliver fertilizers and pesticides to crops.
- Use of the water system to deliver fertilizers for gardening (public and private)
- Non-drinkable water systems (fire extinguishing, heating and air-conditioning systems etc.)
- Unused water lines, where the water stand over long periods and whose quality may therefore be diminished.
- Other uses of water for various purposes for domestic and sanitary consumption (in commerce and industry)
Legislation
- Backflow - the flow of wastewater into the water supply system in the direction opposite to the planned direction of the flow. This is caused due to counter pressure - higher pressure on the consumer’s side compared to the supply network or due to low pressure (suction) - a situation where the pressure in the supply network goes down below atmospheric pressure.
- Hybrid connections - a physical connection between a drinking water system and a system where the water is not drinkable.
Existing solutions for the prevention of contaminations: air space and Backflow prevention
- Air space
In order to guarantee that the quality of the supplied water is not diminished, a separation should be maintained as much as possible between drinking water systems and non-drinkable water systems. The safest separation is an air space between the water transport pipe and their use.
- Backflow Preventers
Where air space separation is not possible, the separation can be performed by installing a backflow preventor. It should be noted that hybrid connections between treated wastewater or wastewater and drinking water is prohibited.
Who has the duty to install a Backflow Preventer?
A. Places of business
Regulations stipulate that a business owner using the water system must install a backflow preventer at the origin of the water system and check its regularity once a year. For this matter, a business is:
- Requiring license as outlined in the addendum to the People’s Health regulations (installment of a backflow preventer), 1992.
- Laboratory
- “An agricultural farm where irrigation is made by a system that includes a device delivering substances into the water system or where pesticides are diluted with water”
- Chicken farm or dairy-farm
Regulations prohibit a water supplier to supply water to a business owner who failed to install a backflow preventer or failed to check it on time, and stipulate that he has the right to install or check the backflow preventer on the business’ premises and charge the owner for the expenses.
B. Private houses and apartment buildings
In private houses and apartment buildings, the potential sources for the pollution of the water system are: fire extinguishing systems and fertilizer systems in the yard and/or balcony and/or inside the home
The responsibility for installing a backflow preventer lies with the House Committee concerning a fire extinguishing system and a gardening system that belong to the building, and if a resident uses a fertilizer system in his home, the responsibility lies with him.
The installation of backflow preventer devices and their periodical check will be performed by an installer qualified by the Ministry of Health. In addition, the model of the backflow preventer devices must be one which was approved by the Ministry of Health.
