The city inspectors and the Health Department got involved. Apparently the previous owners had tried to re-route some of the drain lines to the back yard. The outflow pipes in the septic tank and grease trap were broken and would not drain properly. Luckily, all this happened with rain water and we were able to correct the situation before installing the new plumbing lines. We have set up our plumbing system so that in the future we can separate some of our grey water and reduce the burden on the septic system. This has to be coordinated with the Health Department and will be discussed in detail later.