Backflow Prevention Program

click for common backflow definitions

click to read about actual backflow incidents

            The purpose of this program is to protect the public water supply system of the City of Wayne from the possibility of contamination by isolating real or potential sources of contamination or pollution that may backflow or backsiphonage into the public water supply system. Any arrangement whereby contamination due to backflow or backsiphonage can occur is called a cross-connection. Cross connections between potable water and potential pollutants are encountered everyday by just about everyone, the potential cross-connection between potable water and wastewater occur in the sink and bathtub. Sinks and bathtubs are protected by an air-gap. An air-gap is the distance between the faucet and the flood rim of the sink or tub. I has to be at least two supply pipe diameters, measured vertically above the top of the receptacle and in no case less than one inch. Some mop sinks and laboratory sinks are equipped with faucets that allow hoses to be attached that extend below the rim of the sink, this is a cross connection between your drinking water and wastewater. If you had a plugged sewer and waste backed up into your sink, and your repairman broke a water main while fixing the plugged sewer, all that waste could be backsiphoned through the hose into your water supply line as well as the public water lines. When the water is turned back on guess what you are drinking. That’s right, water that has been contaminated by wastewater.

                How many of your water softener’s drain lines are stuck in a drain or hard plumbed into the sewer line? If they are, they are cross-connections with the potential of polluting your drinking water. Yard hydrants and hose bibs are used with a hose to fill buckets, fertilizer tanks, wash cars and all the other things you do with a garden hose, everyone has the potential for a cross-connection. Installing hose bib vacuum breakers can control 90% of “all” cross-connections.

                Almost all businesses that use water have the potential to have a cross-connection. Some are a greater health risks than others. Examples of consumers that pose a health or pollution hazard to the public water supply system in Wayne are:  Hospitals, Mortuaries, convalescent homes, film laboratories, chemical and petroleum storage facilities, sewage treatment plants, power plants, car washers, laundries, boilers or cooling systems, veterinary and pet grooming, beauty salons, barber shops, fire suppression systems, schools and colleges. This is only a partial list, and your imagination can show you the type of pollutant and the degree of hazard that could backflow into the public water supply system.

                The City of Wayne recognizes these potential backflow areas, and has done and is doing several things to ensure the safety of our public water supply. They have adopted an ordinance fashioned after the state regulations on backflow control. This ordinance recognizes the potential for backflow and states “An approved backflow prevention device shall be installed between the service connection and the point of potential backflow into a consumer’s water supply system when in the judgment of the water commissioner a health, plumbing, pollution or system hazard exists.”

                Every five years surveys are sent out to every consumer in the City of Wayne. Surveys are used to identify a business or homeowner who may have a potential cross-connection. These surveys need to be filled out by each customer or owner and sent back to us. We have to have a 100% return on these surveys. We sent out 2200 surveys in 1998 and did a repeat in 1999. We are still 235 surveys short of reaching the 100% return. We are going to be sending out those 235 again so please send them back, city ordinance requires it.

                Hose bib vacuum breakers are required on all hose bibs. As stated earlier in this article, this can eliminate 90% of all cross-connections. The City of Wayne is going to offer these at our cost of $6.00 and can be picked up at City Hall where you pay your utility bill. If you decide to purchase your own from a hardware store make sure they are frost-proof, self-draining units. All new instillations of hose bibs in Wayne should already have vacuum breakers. If you have any questions about a hose bib or if you are unable to install it yourself please call the water department at 375-5250 and we will help you in anyway we can.

                Most of the businesses and schools in Wayne have been inspected and have appropriate devices installed in their service line or on appliances. Those of you who have testable devices need to have these tested yearly and send a copy to the water department so we can keep them on file. This is required by city code and state regulation. All testers have to be Grade VI certified by the State of Nebraska. Woods, Volkman, and Johnson Plumbing all have Grade VI certified employees that can test backflow preventers. Any business or school that has not completed a survey or does not have test results from their devices on file will be re-inspected and any violations of the backflow ordinance will have to be brought into compliance.

                Fire suppression systems that have testable backflow prevention devices also need to be tested every year. Testing of these devices has to be inspected by a certified fire suppression specialist. Bullseye Fire Protection of Norfolk is an example of who does this kind of testing.

                Backflow prevention is a necessary tool to keep our water system safe. It takes a lot of effort, time and money to make it work. Cooperation between the City and you, the consumers, is a vital part of a good program. When you get surveys in the mail fill them out as soon as possible and send them back to us. Hose bibs vacuum breakers can eliminate 90% of potential back flows. Please purchase and install one on each hose bib you have. If you are unable to install one yourself please call the water department at 375-5250, we will be glad to help you. Commercial consumers need to have all devices tested once a year and send a copy of the report to the Wayne Water Department. Anyone who hasn’t been inspected, has not turned in a survey, or has not tested their device and sent us a report will be inspected in the near future. If we all work together we can eliminate backflow situations from occurring in Wayne. The goal is to deliver safe water to everyone in Wayne every time they turn on a faucet. Another benefit of having a good program is we may not have to chlorinate when the new groundwater rule goes in effect if we are up to par.

 

Air gap separation
A physical space that is present between two objects.
 

Backflow
To reverse the natural and normal directional flow of a liquid, gases, or solid substances back in to the public potable (drinking) water supply.
 

Backflow prevention
To stop or prevent the occurrence of, the unnatural act of reversing the normal direction of the flow of liquid, gases, or solid substances back in to the public potable (drinking) water supply.
 

Backsiphonage
A liquid substance that is carried over a higher point. It is the method by which the liquid substance may be forced by excess pressure over or into a higher point.
 

Contamination
To make something bad. To pollute or infect something. To reduce the quality of the potable (drinking) water and create an actual hazard to the water supply by poisoning or through spread of diseases.
 

Cross-contamination
The mixing of two unlike qualities of water. For example the mixing of good water with a polluting substance like a chemical substance.
 

Decompose
To decay or rot.
 

Flood rim
The point of an object where the water would run over the edge of something and begin to cause a flood.
 

Irrigation
Water that is especially furnished to help provide and sustain the life of growing plants. It comes from ditches. It is sometimes treated with herbicides and pesticides to prevent the growth of weeds and the development of bugs in a lawn and a garden.
 

Pollution
To make something unclean or impure. Contaminated.
 

Potable
Good water which is safe for drinking. Non-Potable: A liquid or water that is not for drinking.
 

Prevention
To take action. Stop something before it happens.
 

Submerged
To cover with water or liquid substance.
 

Venturi
If water flows through a pipeline at a high velocity, the pressure in the pipeline is reduced. Velocities can be increased to a point that a partial vacuum is created.
 

Water Purveyor
The individuals responsible to help provide, supply, and furnish quality water to a community.

 

Examples Where Backflow Incidents Occurred

 

1.       In 1932, in the worst case in Nebraska history, during a 5-week period more than 10 percent of the 347 children in Huskerville, NE, contracted polio. A study of the water revealed that the afflicted children lived in areas where flush valve water closets lacked vacuum breakers. A time relationship was found also in places where extreme fluctuations of pressure in the water mains might have permitted wastewater to be forced in the drinking water supply.

2.       80 students at a midwestern university reported remittent fevers, malaise, headache and anemia. Their symptoms led to a diagnosis of undulant fever (brucellosis). Only those students who had been working in the cultivation of bacteria in one of the laboratories were affected. The mystery was how the brucella cultures in the laboratory could have been transmitted to the students. Finally, a hose was found connected to a faucet in the laboratory. The other end of the hose was submerged in water containing brucella. A temporary reversal of pressure, possible the consequence of a demand for water in another part of the system, had drawn the water teaming with brucella into the drinking supply. Of the 80 students affected, 1 died. As you can see, the problem we are dealing with can have deadly results.

3.       In 1972 in a west coast industrial plant, a submerged inlet was used to supply a lye vat with water. On the other side of a wall from the vat was the employee’s shower room. Fortunately, the cross connection was discovered before harm was done. However, company officials were alarmed that employees could have been taking showers with water contaminated with lye from the vats.

4.       In a case involving an automatic car wash, gallons of concentrated detergent were injected into a city water system. The detergent was found in resident’s drinking water more than a block away. The cause was reported as an unprotected cross connection in the car wash plumbing lines.

5.       In Newton, Kansas, in 1942, one of the town’s two water supply mains had been taken out of service on September 2, 7 and 8. A house service connection to this main supplied three frost-proof hydrants, and two frost proof toilets. It was assumed, from subsequent events that some unknown person or persons tried to obtain water from a hydrant connected to the main out of service. When no water flowed the person evidently left, leaving the valve open. On September 10, it was discovered that a neighboring sanitary sewer was clogged and the sewage had overflowed into the hydrant box. It was learned that for two days, all the sewage from the toilets of ten families had been permitted to flow into the water main. When the main was put back into service, there was no attempt to sterilize it. More than 2,500 persons in all parts of the town suffered enteric disorders as a result. Stool cultures and pathological findings from two autopsies diagnosed the illness as bacillary dysentery. In addition to the widespread illness in the town, it is believed that the infection was carried aboard a number of troop trains, which were watered in Newton at that time.

6.       Backsiphonage caused by defective plumbing in a new student nurses building was blamed for an outbreak of disease in 1963 in Ohio. It was necessary for 100 of the student nurses to be quarantined for two weeks. Bacteriological examination showed that the drinking water was contaminated. The city health commissioner theorized that salmonella was brought into the building by some of the girls and then spread by defective plumbing.

7.       A tank truck filling from a city water supply caused a serious emergency involving the contamination of a water supply. In 1971, a contractor using a tank truck with a rig designed to pump and spray a mixture of water, fertilizer, grass seed and wood pulp working on the grounds of a subdivision. The contractor was using a direct connection to a fire hydrant to fill the tank with water, which was then mixed with the fertilizer and other ingredients. A high-pressure pump then mixed with the fertilizer and other ingredients. A high-pressure pump then sprayed the mixture onto the ground. As the wood pulp circulated through the tank piping system, it plugged one of the lines while the pump continued to run, creating a very high pressure in the tank. This pressure was higher than the water supply system pressure and forced the solution of fertilizer into the water supply. Several people in the subdivision became ill after drinking the water, but the contamination was discovered and quick action in flushing and disinfecting the lines eliminated the danger.

8.       Eleven caddies experienced nausea, severe vomiting, and abdominal cramps after consuming a “soft drink” at a New York golf club in 1964. The beverage was commercially prepared by the mixture of syrup with carbonated water in a vending machine. Investigation revealed that a pipe carrying water into the machine was connected to the recirculating hot water system instead of the drinking water system. The day before the incident, a lye and chromate solution was added to the hot water system. 

9.       A New England town had two separate water systems – one for safe drinking water, and the other for fire protection. The fire protection system pumped untreated water directly from a river. At an industrial plant in town, workers mistook a fire system line for a fresh water line and connected a bubbler to it. After drinking the water from the bubbler, seven people developed infectious hepatitis and over a hundred people were ill with gastroenteritis.

10.   In 1967, an outbreak of gastroenteritis occurred at a small private college in Pennsylvania. Almost one quarter of the 700 students and faculty were affected. The only factor in common to all those who became ill was the consumption of water or food that had been prepared using water from the school water system. Investigation of the water system revealed that a water line had broken in the kitchen of the school cafeteria, flooding both the kitchen and the cafeteria. Cross connections were found between the sewage system and the water system that could have resulted in backsiphonage of sewage into the water system as a consequence of negative pressure during the break in the water line. It was concluded that the outbreak probably resulted from the presence of Shigella Sonnei in the water system. The incoculum would have been of sufficient size to overcome the chlorine in the water.