Frequently Asked Questions (FAQ)

I am new in town and would like to know how to get a copy of your latest design standards. Also, where would I find manhole spacing requirements for storm drain and sewer based on mainline pipe diameter??

Thank you for using our FAQ system.

You can access the latest County design manuals on our website ( by following the link below.

MH spacing requirements for storm drains are as follows.
30" dia or less 300 feet
31"-44" dia 400 feet
45" dia or greater 500 feet

Sewer MH spacing is a maximum of 350 feet regardless of pipe size.

If you have additional questions please contact our Land Development Division at (626) 458-4921

  Link to LA County Design Manuals
Design standards LDD regional planning subdivision land development tentative map parcel tract lot split clearance bond drainage concept bulk grading private drain transfer sewer area study LID improvement future surface mining