DALLAS -- Driving up to the Dallas Water Treatment Center gates and reading signs warning of POISON with a skull and crossbones is not very comforting.
"That's chlorine gas is all, just like cyanide," Kenn Carter, assistant public works director said with ease.
However, upon learning poly aluminum chloride, soda ash, ammonia and fluoride are used in small amounts to keep our drinking water germ-free can be reassuring.
Arguments over whether Drano is safe to use to de-clog drains and the new medication disposal program to keep drugs out of our water prompted an investigation to find out where our water in Dallas actually comes from.
Carter, the tour guide, said he only gives about six or seven tours of the Dallas water system each year. After the 9/11 terrorist attacks, he said he was not allowed to give tours at all, but offered trips to the center again about two years ago.
We headed west of Dallas to the water intake pump station, built in 1959 and expanded in the 1970s, 1993 and again in 2008. Before the 1970s, Carter said Dallas residents received water from Rickreall Creek and some tributaries. The water was not cleaned or assessed until adding chlorine in later years.
Today, the water rushes from the Mercer Reservoir above, travels about five miles, leaves and debris are screened out, and then it is piped into the intake pumping station. This raw water is pushed up several hundred feet by three energy-efficient pumps a little more than one mile to the treatment center.
Yes, this is the place with the poison. It's hard to believe that this high-tech facility is out in the country. The water flow is measured and the staff decides how much water to treat that day. More water needs to be treated in the summer when more is used for lawns and gardens, Carter said.
The treatment center is Herb Crumley's world. Crumley is the water treatment facility operator.
This day, Crumley was treating about 2-million gallons. The raw water is pumped into the center and treated with poly aluminum chloride that grabs particles like sediment in a big clump.
"It's sort of like a snowflake forming," Carter said.
The snowflakes of sediment settle to the bottom of large tanks and the water is filtered through layers of rock and sand, including ground garnet -- a semiprecious stone.
Next come injections of chlorine, soda ash, ammonia and fluoride. The chlorine disinfects, the soda ash adjusts the concentration of hydrogen ions (or pH), the ammonia acts as a preservative of the chlorine and the fluoride builds strong teeth, Crumley said.
The clean water is held in the 2 million gallon tank on site and flows by gravity to reservoirs on Clay and Main streets. From the reservoirs it is piped into your faucets.
Carter said the average drop of water spends 4 days in the system in the winter and 1.5 days in the summer.
And what about the Drano and prescription drugs? Carter said the waste water treatment plant takes care of cleaning those. Drano gets diluted and disappears, but the medications are a hurdle, Carter said.
Medication with hormones are not removed by microorganisms that clean the water and affect fish in streams.
"I can only imagine what fish might do if given other drugs like Viagra," Carter said. He said it is important that people dispose of medications correctly to protect humans and wildlife.
For more information about how Dallas drinking water gets to your house, contact the Public Works Department at 503-831-2339.