Plumbing Engineer - Columns: February 2013: Code Classroom
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Plumbing Engineer - Columns: February 2013: Code Classroom

How safe is our water supply?

By Ron George,CPD,
President, Ron George Design & Consulting Svcs.

I was at home one morning, and while in the bathroom I heard a strange gurgling sound coming from the walls. I went over to the toilet and flushed the toilet. It flowed briefly, then it started gurgling and air was coming up in the tank from the fill valve in the toilet. Soon after that, the gurgling turned into a hiss, as air was being sucked in the open fill tube because the float valve was still in the open position. So, I reached down and closed the fixture isolation valve. I went to the sink and opened the sink faucet and heard the sound of air sucking in and gurgling sounds. I was on the second floor of my home and when I opened the faucet, air was rushing into the pipes as water was draining out of my pipes and back into the water main and what I eventually discovered was an open ditch down the road. I had just witnessed a backflow incident.

Later that day at work, I was talking to one of my new 3D BIM CAD operators. He is very health conscious and he drinks a lot of water every day. He had a large drinking water container at his desk. I said that was a good idea to drink bottled water. He said he usually just refills it from the faucet. I asked if he had a water filter or charcoal filter on his kitchen faucet at home. He replied, “No, this city has some of the best water around.”

I said that may be true most of the time, but every water system experiences a water main break, a fire or some other event that will disturb the water main and lead to a backflow incident or an incident where the biofilm and sediment is flushed or disturbed to the point where the water becomes cloudy and contaminated. I told him I have experienced this on frequently at my office in the last few months and that I experienced it at home just recently on several occasions.

Water flowing from the tap at my office has been noted as cloudy and in one case yellow or tannish in color. Shortly after the last time the water was cloudy, we noticed a strong chlorine odor in the water. This was most likely the water department responding to some form of disturbance in the water main by hyper-chlorinating the water supply to kill bacteria that could have been in the biofilm that was disturbed and released or washed down the water main.

I have experienced this on a firsthand basis while out flushing and pumping fire hydrants for our volunteer fire department in the fall. The first water flush from the fire hydrant is usually the black and brackish water that sits stagnant in the fire hydrant branch. The water flowing from the hydrant changes from black to dark orange to orange and then yellow in color for up to about a minute. The water then starts to run clear. While flushing fire hydrants, we have flushed all kinds of debris out of the hydrants and the water mains including gloves, soft drink cans, garden hoses, stones and pieces of wood. I particularly remember one day while flushing water onto a paved area we saw the orange iron oxide potato-chip-looking residue, sand, grit and stones lying all over the paved area after the flushing was completed. The debris flushed out is usually whatever was lying in the bottom of the pipe or stuck to the walls of the pipe when it was assembled. The normal flow for drinking water in homes is such that the normal flow velocity in the water main is very slow. The water main is designed and sized for a fire flow.

Considering the fact that safe drinking water is vital to human survival, it seems strange that the utility companies (water purveyors) charge so little for water. Most water utilities are operated as nonprofits by volunteer water and sewer boards elected to serve the public. The main concern seemed to be to keep the price of the water really cheap.

I would prefer water that is safe rather than cheap. The courts have deemed that water is a product and not a service to the public. The water purveyors take the raw material and process this material through their water treatment plants and then sell this product to their customers at a rate that just about breaks even. The local water utility board I served on seemed to always be about a year behind from the time the city engineer and the water treatment plant presented the costs to the water and sewer board. This was when we found out what our actual costs were. The political process for changing water rates takes a long time, so in some cases we lost money billing at the old rate until the formal process of raising the rates could be completed.

Water is sold to the public and it is implied that it is safe to drink. Water is safe to drink most of the time. But, there are those incidents where something unusual happens and there can be a disruption of the water supply, which can cause the water to be contaminated. If there is not good enforcement of backflow preventer requirements in the codes by inspectors, then the water supply can be contaminated. So if you drink from the faucet at home it is probably a good idea to use a drinking water filter unit. It should be noted a filter unit cannot always protect you from some chemicals that can backflow into the water system. The reverse osmosis filter units are best. Cartridge filters can be paired with an added charcoal filter also remove the chlorine taste from the water.

The discussion turned to safe drinking water and the code requirements in chapter 6 of most plumbing codes, which covers backflow protection. Backflow protection must be followed by everyone or the system can fail. We must provide backflow protection at every potential hazard or source of backflow. The water utility or water purveyors deliver the water through a series of water mains and building service pipes to their customers’ water meters. Once the water is delivered through the water meters to the customers, the water purveyor does not want this same water to return back through the meters and out into the public water supply.

They have an obligation to protect one customer from another so they provide requirements for backflow preventers after the water meter. This type of backflow prevention is referred to as “containment.” The clean water is delivered to a customer and contained or protected from backflow to the water main with a master backflow preventer on the water service pipe serving that properties’ building water distribution piping system.
Most customers manage to contaminate the water they use and normally this contaminated fluid passes to the waste collection system. Unfortunately, the water sometimes reverses direction to another fixture within the water distribution system or back through the water meter. This reversal of direction is called backflow. The most common type of backflow is backsiphonage.

Backsiphonage is caused by a sudden loss of pressure in the public water mains. This is what I experienced in my home. This loss of pressure can be caused by a broken water main, a fire nearby where the fire department is using large quantities of water, or simply by opening a fire hydrant to flush or test it. Any buildings near the break or the fire hydrant being used will experience a lowering of the water pressure. This is the time backsiphonage can occur.

Backsiphonage is not a problem if every plumbing system is built and maintained according to the plumbing code. Water might never be contaminated if all customers’ plumbing systems were designed, constructed and inspected by individuals that fully understood the hydraulics of moving water. Water might never be contaminated if homeowners, who are allowed to make their own home improvements and repairs under “Home Rule,” fully understand hydraulics and the local plumbing code and would never think to take short cuts to save a few dollars. Water might never be contaminated if products sold at hardware stores, home improvement centers and plumbing supply houses were absolutely safe to use under all hydraulic conditions.

We have all seen non-code-compliant products sold in home centers. This is because we cannot restrict the sale of a product. However, if that homeowner pulls a permit and if the inspector is sharp and catches it, he or she will red flag the installation causing, the homeowner to remove the non-code product.

There was a push one time to restrict the sale of a certain water closet fill valve that had a submerged inlet. The sale of the product could not be restricted, because it was possible to install a backflow preventer prior to the fill valve on the fixture supply branch causing it to be in compliance with the code. So it can be installed in accordance with the code, but hardly ever is. Plus, the non-code products are always the cheaper products.

Unfortunately, many homeowners, architects, engineers, plumbers, pipefitters, contractors, inspectors and health officials have not had the proper training necessary to protect your water supply.

Your neighbor could be watering their lawn with a sprayer that has a pesticide or herbicide container attached, or they could be flushing the radiator in their car with a garden hose, or simply adding water to their swimming pool. Any contaminant in contact with the end of their garden hose may wind up in your water piping if there is a drop in pressure in the water mains, such as the drop that happened in my home.

Every utility company in the U.S. receives calls concerning “blue” water at the customer’s kitchen sink. This is usually from a backflow incident where the blue tidy bowl water siphoned into the water main, and then upon restoration of the water supply, blue water flowed everywhere.

Now don’t go out and buy bottled water. It is not regulated as carefully as your tap water. You have no idea what you are drinking when you buy any of the bottled waters that are mineral waters. A study noted very high bacteria levels in various brands of bottled water.

On a recent trip overseas I noted that everyone boiled their water and then drank it in tea. This was because the country did not have a safe public water supply and the only way to kill bacteria in the water was to boil the heck out of it and flavor it with tea.

The situation is not hopeless. We just need to remain vigilant and educate the industry and the public on how to provide safe drinking water. There are very effective ways to protect you and your neighbors’ drinking water. Just don’t drink cloudy water.

Ron George is president of Plumb-Tech Design and Consulting Services LLC. He has served as chairman of the International Residential Plumbing & Mechanical Code Committee. Visit www.Plumb-TechLLC.com, e-mail Ron@Plumb-TechLLC.com or phone 734/755-1908.

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