Booster Pump Station Wet Wells - are they reviewed?
Most Colorado water professionals already know that we have long focused our review efforts on new and modified facilities. We do not typically review booster pump stations unless the station includes treatment, such as the addition of a chemical to boost the disinfectant level. What many do not realize is that, because many booster pump stations include wet wells that meet the regulatory definition of a finished water storage tank under section 11.28 of Regulation 11, such tanks require division approval prior to construction or modification. 11.28(1)(c) “FINISHED WATER STORAGE TANK” means a tank or vessel owned by the supplier that is located downstream of the entry point and is not pressurized at the air water interface. Pressurized storage tanks are not included in the definition of finished water storage tanks.The most direct way to determine if a booster pump station has a wet well is by looking at how water is supplied to the booster pump. Booster pump stations are either fed directly from the pressurized potable water distribution system piping or from a finished water storage tank. When fed directly from the distribution piping, the booster pump station does not break the inlet head in a finished water storage tank (wet well) and the incoming water does not have an air-water interface. These types of pump configurations may be termed “in-line pumps,” “barrel-” or “can-style” pumps. They are not subject to the storage tank rule.
At times, booster pump stations must break the source water pressure prior to pumping.The source water typically enters an onsite wet well, which means that it has an air-water interface that could potentially expose the finished water to contaminants. Booster pump stations with wet wells can have a variety of potential configurations, but most commonly use vertical turbine pumps. In all cases, though, the booster pump station has a wet well with an air-water interface that meets the definition of a finished water storage tank. These vessels are subject to the storage tank rule, which includes periodic inspections.
According to Regulation 11, they also must receive design approval from the division prior to construction or modification. Unfortunately, due to a department oversight, the current design criteria for potable water systems do not have well defined requirements for this type of finished water storage tank. We plan to develop design criteria during the next stakeholder process, but until then, we will only be evaluating booster pump station wet wells in the following cases:- We will begin accepting and reviewing construction applications for all booster pump station wet wells following adoption of the next design criteria revision.
- We will complete design reviews for any booster pump station tanks if they are part of a larger infrastructure project subject to the design review application process.
- We will investigate booster pump stations during sanitary surveys but will not issue violations for sanitary defects until 2022.
Have questions?
If you are planning to construct or modify an existing booster pump station wet well and you want additional information, contact
Bret Icenogle, engineering section manager
303-692-3278
➽ Bret Icenogle, engineering section manager
➽ Bret Icenogle, engineering section manager
