Runoff that smells terrible? Honestly, just cause it smells a tad foul doesn't mean much, unless it's runoff from an industrial site... lol. While I don't know if cannabis does this, but there are some plants used in bio remediation processes cause they can absorb toxic compounds directly through their root system and sore it in their flowers and such. I would guess your water is nothing but nutrient rich stuff given your plants are 8 footers, but do ya know what's in it? ... If it's just doo doo in the water then your plants will not taste like doo doo.