My Mother-in-law bought a older home a few years ago. The kitchen had been modified, including the plumbing. With only 2 people living there, and doing small wash loads, the drains worked fine, although the pipes gurgled when the washer or dishwasher were being used. Now there ar 5 people in the home, and washer loads have gotten bigger, and now the drains are backing up when the washer is being used. The lines appear to be OK as a garden hose in the washer drain and the kitchen facuts on flow fine, but as soon as the washer is hooked to the drain, the lines start to back-up. One thing I've noticed is that there is appears to be no vent to these lines. Could this be the problem? There are no clean outs on the system, so to really clean the line would require installing a clean out. Thanks for the help.

Washers put out a lot of water on the drain cycle. They also collect lint in sharp edges of the traps and drains. Sometimes you can't see a vent line for a washer box since it inside the adjoining wall. If you can see where the washer drain line makes an ell or enters the main drain, you can put a clean out there if you have space. Gurgling pipes may or may not be an issue. Fast flowing water down a drain creates a vortex and sucks in air. It's hard to snake a washer drain because of the trap. Look for a cleaanout farther down the line, start there and then go with a new cleanout if practical.