How to Keep Rainwater Clean in Large Water Storage Tanks

When you harvest rainwater, it is important to filter the water before it reaches the water storage tank. However, very small particles such as pollen and oil will often go through your filter mesh and into your storage tank. This causes your water to sour and the particles in the tank to build up over time.

Particles heavier than water (such as pollen) will fall to the bottom of the storage tank and form a layer of sediment.

A Calmed Inlet at the bottom of your water tank will ensure that the water flowing into your tank will not disturb the settled sediment. The shape of the Calmed Inlet means that water is pushed upward into the tank. The upward flow of the water into the tank oxygenates the stored water. This oxygen-rich water prevents anaerobic reducing conditions forming in the storage tank and ensures that the water stays fresh and keep your rainwater clean.

Particles lighter than water (like oil) will float to the surface of the stored water (the 3P Technik Overflow Siphon will skim these particles away to Waste).

The Calmed Inlet is the 2nd step of the Four Steps of Rainwater Harvesting (the Overflow Siphon is the 3rd).

Technical Information

• Material: Polyethylene - Black
• Takes Pipe Sizes: DN110, DN125 (4" pipe)
• Weight: 0.5Kg
• Overall Dimensions: W:320mm, D:135mm, H:155mm,

Included Components

Calmed Inlet only

Other Options

This Calmed Inlet can be purchased as part of a Rainwater Harvesting System for Water Storage Tanks.

Useful Information

How to filter Rainwater from a roof - blog post.