i have a terrible mosquito problem, hopefully you all can help. i live in a duplex with a shared back porch. the porch floor is wooden and there is about 6 inches under the porch where the water from the washing machines from both our houses drain. i have a 3 year old and he has 3 kids living with him so our washers do get used daily, sometimes 3 or 4 washes a day between us. i dont know if letting the washer water just drain onto the ground is the way it is supposed to be but all of the duplex are the same way. i just happen to be lucky enough to have a porch for the water to go under. is there anything we can pour under the porch or through the washer drain that will kill the mosquito larvae? its to the point know that the porch is getting unusable.