I doubt that it's wise to use for potted plants in part because the potting mix lacks the various microbes normally in soil which can cope with grey water.

And in an in-ground planting, it's wise to limit use to rinse water rather than wash water.

You might be able to locate specifics from various greenhouse growers, greenhouse forums, and greenhouse suppliers.

And if water restrictions are required in your state, the local water department is likely to have information, possibly also the state university.