On Saturday morning we were called out to a major shopping complex that had sewer drain overflowing in their downstairs storage area. When we arrived on site, the maintenance manager met us and escorted us to the work area. Beside the stairs were a set of gumboots that he pointed at and said “You’re going to need them.” I then looked down the staircase and saw there was about 150 mm of raw sewage just built up on the bottom floor… It was like a swimming pool of poo!!!
We haven’t seen a blockage like it before, it had gone unnoticed all Saturday morning up until about 11am. There would have been hundreds of people at the shopping complex flushing the drains morning all morning. After a quick investigation we realised that the surge had been overflowing out of the showers floor waste, click on the video link and see for yourself it was like a river flowing out of the shower area when we opened the door.
Diagnosing the sewer drain problem
It was clear that this blockage was the result of a blockage on the main drain line somewhere. We started to ask the maintenance manager a few questions about the drainage area and he mentioned all the sewage flows to holding pits and then gets pumped out to the councils drain. So, the first area we decided to have a look was the electrical pump out station located in the underground carpark.
When we went and had a look at the electrical switchboard and the three pumps were all switched out in lockout mode and had the red highlight of failure showing on the control board. We turned on all three pumps to manual override. Two out of the three pumps activated. Pump one was faulty and switched back off; pumps 2 and 3 remained on and started pumping sewage to the council’s drain line. The control board has a high-level sensor for when the sewage levels get above the normal height, but for some reason the high level sensor alarm did not activate.
We stayed at the control board for about 20mins to ensure the pumps stayed turned on. We then went and chucked the gumboots back on and went down into the basement area. The sewage water level was going down and it was all flowing back down the shower drain!
The maintenance manager got in touch with the pump specialists to attend site and do a bit of fault finding on the system. I’m very glad that we did not have to clean the mess up because it was pretty bloody horrible. We didn’t even have to use the high pressure water jetter or CCTV camera to clear the blocked drain. It was a matter of turning a few switches on a control board to clear the blockage. I wish all our emergency plumbing callouts were that easy to fix!