Trenchless Sewer Repair Los Angeles. Trenchless sewer repair is a process of installing a seamless liner in the existing Los Angeles sewer pipe. Trenchless sewer repair can be complete in less than one day, saving your landscape, and any property damage that would occur with the old method of excavation. The Perma-Lateral trenchless sewer repair system is very popular in Los Angeles due to our quality controlled materials and 24/7 technical support.