Note that most municipal water is recycled in similar fashion (something like 90% of tap water ends up in the sewers directly, and that's low-balling it)--which

Note that most municipal water is recycled in similar fashion (something like 90% of tap water ends up in the sewers directly, and that's low-balling it)--which means you can get great mileage out of municipal systems just by sticking your water treatment intake downstream of your wastewater treatment effluent, although people are somewhat squeamish to discover that this happens. Agricultural use is pretty much the most effective way to export water out of the watershed--the water that is used in the crops is more likely to be lost due to envirotranspiration or simply literally part of the weight of the crop that is exported (especially for leafy crops like lettuce).