 Ken Moon answers your questions around the house. Question. If you're out in the country and you're on a septic system, can you have a dishwasher? Well, yes, you can, especially since the soaps have changed. Quietly, the manufacturers of dishwasher soaps have removed the phosphates from them. There was a big environmental stink up in Washington state, so the soap has changed, which means it's much less harmful to bacteria in your septic tank.