Managing Rainwater Tank Overflow

Rainwater tank overflow issues are common problems for rainwater harvesting systems — but they can be prevented using a few simple tips. An overflowing tank can be hazardous, but following a few precautionary measures can remove most of the major risks an overflowing tank introduces to a rainwater collection system. Keep reading to learn how to prevent excessive or hazardous rainwater tank overflow from happening.

Common Causes of Rainwater Tank Overflow

An overflowing tank is most likely the culmination of a few different causes. Overflow issues can range from mild to severe with most problems being resolved by proper maintenance and inspection of your rainwater harvesting system. Here are some of the more common causes of rainwater tank overflow.

tank overflow

1. Incorrect Water Inflow Levels

Too much water inflow without an equivalent amount of outflow is the number one cause of overflow issues. This usually occurs when an overflow device is not present or has become clogged, when sudden heavy rainfall occurs or when the rainwater storage tank was at or near capacity prior to rainfall.

2. Misaligned Outlets

If your system has two or more rainwater storage tanks combined, then double-check to make sure that connecting outlets are not misaligned. If overflow issues occur between tanks, it is possible that the outlets are misaligned and proper water overflow from the primary tank to the overflow tank is not working as efficiently as possible.

3. Buildup of Surface Particulate

Even with floating filters inside your rainwater storage tank, a buildup of particulate matter on the surface of the water can cause problems when that water tries to flow through filtration systems to be dispersed. If the screen size on your floating filter/intake is smaller than that on your pre-filter, it may also require more frequent cleaning/maintenance.

4. Gumming on Overflow Screens

The holes in an overflow tank outflow mesh are small, and things like trapped debris and bugs can form a sticky layer of organic matter over time. This in turn blocks the outflow and causes spillover.

3 Tank Overflow Maintenance Tips

The good news is that there are some simple steps you can take to prevent excessive or hazardous rainwater tank overflow. You can mitigate water tank overflow by using standard PVC piping or a WISY multifunction overflow device and following these maintenance tips.

rainwater tank overflow

1. Check and Clean Regularly

This includes all pre- and post-filtration screens, overflow siphon, floating filters/intake and purifiers included in your WISY 4-step system prior to pumping water into your residence or commercial site.

2. Routine Inspection of Catchment and Downspouts

Check your catchment and downspouts to ensure they are free of excess debris and unwanted particulate matter. While most pre-filtration systems will filter out larger particulate matter and debris, ensuring that your catchment doesn't have regular contamination from nearby foliage can save you a lot of time in the future.

3. Create an Exit Path for Incoming Water

Implementing an overflow device to clear excess water and particulate is one of the best ways to manage rainwater tank overflow. A WISY water tank overflow device will siphon particulate off the water surface which will reduce the gumming effects that particulate can cause on screens and filters.

Find Rainwater Tank Overflow Options at RMS

Whether you are using rain barrels or underground rainwater collection tanks, managing water overflow is paramount to managing your rainwater harvesting system. RMS has rainwater tank overflow options for your program, including overflow devices that help you manage water inflow and outflow and prevent issues. Find all of your rainwater collection supplies online at RMS.

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