Substructure Maps and Sewer Maps
https://pw.lacounty.gov/mpm/substructure/
Zoom into the location/address that you are trying to obtain substructures for and click on the box that the location is within. If it is a stretch of road or area that is larger than one box, you will need to open each box with the process above for each DC-*** map that you are looking for.
https://dpw.lacounty.gov/smd/sewernetwork/
Use the interactive map to find the location (address/general area) of the sewer map you are looking for. Left click on the location near your desired address and a box with View Map and View Overlay will appear. Click the View Overlay button. A PDF should appear. Note the letter and numbers associated with the address or areas you are looking for.
https://dpw.lacounty.gov/smpm/landrecords/SewerPlans.aspx
Click on the corresponding letters (P.C., C.I, etc.) and then the map number (Book 06500, Book CI1500, etc).