Is water running from a main in your neighborhood? It may be a disinfection blow off point. Click to learn more about this process.

Why is there running water at a new main construction site?

Here’s how we disinfect water mains with blow off points

If a new water main is installed in your neighborhood, you may see running water coming from a one-inch pipe sticking out of the ground and wonder why.

What you’re seeing is a blow off point and sampling station that’s critical to ensuring we deliver safe drinking water to your home once the new main is turned online.

It’s the final step of new main installation and it’s important that this area is not tampered with and remains running until one of our crew members shut it off at the end of a several-day disinfecting and testing process.

So, what are we doing?

  • Flushing Cleaning – We run water through the new line to flush out any dirt, debris and air that entered during construction.
  • Pressure Testing – Then the pipe is hydraulically pressure tested, usually to 225 maximum pressure per square inch, to ensure there is no water leakage or weak joints.
  • Disinfecting – To disinfect the pipe’s interior, a strong chlorine solution is added. This process takes 24 to 48 hours and sometimes longer for larger diameter or long sections of pipe. Following the disinfection, the chlorinated water must be flushed out of the main.
  • Testing the pH Balance – Samples are then taken to measure the pH of the pipe until it meets guidelines. This process can take several days based on the pipe material, size and length.
  • Taking Bacteriological Sample No. 1 – After a pH is achieved within the acceptable range, a bacteriological sample is taken from the sampling station (the pipe that you see the water running out of) for analysis. This is done back at our lab.
  • Taking Bacteriological Sample No. 2 – We must take a second such sample 24 hours after the first. If both come back within guidelines, then the water main is ready to begin distribution of drinking water to customers.

The entire process can take five to six days to complete and water remains running throughout this time to ensure bacteria are not introduced from the outside to the sample station and to maintain high-quality water in the pipeline.

If at any point the water is shut off or the sample station is tampered with in any way – even a single touch of a hand – the sampling can fail and the entire process has to be started again from the beginning.

All of our sampling stations are tagged with notification to not tamper with the assembly. Please heed these postings. It will help us deliver safe drinking water to you on your new main more quickly.

The purpose of this process is to ensure public safety with the installation of a new line. Central Arkansas Water takes pride in following all EPA and Arkansas Department of Health regulations when utilizing this industry-standard process of preparing new mains for distribution.

We understand residents can get curious and worry that water is being “wasted” when they see it running from a sampling station for several days. That non-potable water isn’t wasted because it is ensuring that you are not exposed to potentially harmful bacteria.

We appreciate you letting us serve you by explaining our process and enhance your quality of life by delivering you safe, affordable and reliable drinking water.