Twice a year, the in-service uncovered reservoirs in Mt. Tabor Park are drained and cleaned. To prepare for cleaning, much of the water in the reservoirs is paid out into the system’s drinking water. Once they are ‘drawn down’, the remaining water goes down a drain into the combined sewer system. Once the reservoirs are empty, Water Bureau crews clean them and perform normal system inspections and minor repairs.
Once cleaning and inspections are completed, the reservoir is disinfected, filled to normal operating range, tested to ensure the water is potable and if results come back “clean”, put back into service.
The Portland Water Bureau has drawn down Reservoir 5 in Mt. Tabor Park in order to perform annual spring cleaning procedures. The reservoir is now offline and empty and crews are busy cleaning it. The reservoir will be put back into service in the next few days.