Greywater practicalities: Receiving

To finish up our introduction to greywater, we’ll cover the receiving system. This is my favorite part of the system. We get to think about gardens and trees!

Greywater should not be used to water above the surface (leaves, grass, etc.) nor should it be used to water food. Greywater should be used to apply below-surface watering to non-food plants. Food producing trees are an exception to the “don’t water food rule” as long as the water is applied only to the roots.

Non-pressurized distribution systems are generally well suited for sending a fairly large amount of water to a fairly small number of end points. This makes trees great candidates for greywater receivers. Trees need large amounts of water, and they can handle getting significant doses at one time.

To be most effective, trees receiving greywater should be planted in mulch basins (actually, mulch basins are generally a good idea for trees). Mulch basins allow water to be purified much more effectively than a tree just planted in the ground. A mulch basin starts with a basin with an island in the middle. The tree is planted on the island so that it does not sit in the water. The basin is filled with mulch which both prevents the greywater from being exposed to the surface and slows the flow of water, allowing better infiltration into the soil.

When greywater transitions from the distribution system to the receiving site, it should either flow into an underground chamber or directly into a mulch basin which can quickly prevent it from being above ground. This part of the system must be designed to avoid clogs, both from the greywater itself and from the material that the water is being let into (or slugs, as apparently they sometimes like to crawl up pipes).

I hope that you enjoyed this introduction to greywater. Greywater systems are not for everyone, but I hope that in the future, new homes will default to having separate collection plumbing so that more people can at least have the option of saving water.

In this post and throughout the rest of this series, I use Art Ludwig’s The New Create an Oasis with Greywater as my primary source; it’s considered one of the best resources on residential greywater for the lay reader. Other bits and pieces are mostly pulled from my memory of other books and websites I’ve read. Any mistakes are, of course, my own.