Potable Tank in Water Tower System

FAQ: Can potable tanks accomodate specific fittings and fabric?

Customer had a unique idea for a water tower tank. He was looking to place a collapsible tank inside one of these towers. See below:

Question: I am a consultant and working with a client who has an alternative idea on what would basically be a water tower for potable water. He would like to take one of these containers and put a bladder inside that would fill and collapse with whatever the water level is.

The bladder would need to accept a ball valve at the outlet and a check valve on the inlet side. Since the container would take most of the stress from water accumulating inside, hopefully this would reduce the physical requirements on what the bag needs to do over its lifetime. Other considerations would be: 10 year life free from seam separation, cracks or other defects Temperature capability from -40 to 150 F NSF/ANSI 61 approved for water usage. Various sizes from 150 to 1000 gallon.

Answer: Thank you for your inquiry. Portable Tanks, a division of Water Storage Tanks can build a water tower tank bladder that can be placed inside a supported structure such as a container to effectively operate as a drinking water reservoir for on demand use.

To better understand your application, we would need to get some digital pictures and a dimensional sketch that showed the interior of the tank container so we can see where would be best to place a fitting for fill and drain and also where reinforcements would need to be considered for abrasion or stress over time.

Further items to consider are the climate (whether extremes would be experienced and what those temperatures would be) and lifespan. Tanks have been built to withstand use in extremely cold climates (such as -40 F) and extremely hot climates (such as 180 F).

Typically, a water tower tank bladder is built from a fabric that is either commercial, medium grade, or heavy-duty. Each fabric will differ in terms of thickness and rated contact time. For the long-term use that you have specified, you would probably require one of our thicker fabrics rated for a contact time of about 7 years.

Bladders do come with materials that are FDA and NSF 61 approved for the safe storage of potable water. We recommend that the water tower tank vessel is inspected periodically as part of a maintenance plan and consideration should be given to ensure this works in your specific application.