I am almost done finishing up my ADU in Glendale! Here is a sum up of how long it took me and the process.
1) To get permits and architect: complete and approved took 7 months. Fees for permits. Park and Rec fee, permit fee came out to $10,500 and Architect came out to $5,000. Grand total to pull plans $15,500.
2) Issues I ran into: I originally wanted to expand my Garage into 600 sqft. Currently at 400 sqft. I had to change the roof, and the biggest issue was because I was on the hills I needed a soil report. The soil report for adding the 200 sqft additional i had to dig a trench 6ft down and have load bearings to support. Pretty much needed to build deep like a pool. Because of this the expense for the project was coming out to be past my budget est about 120k for it all.
3) What I did: I went back and just kept my same 400 sqft with no addition. Cost of project went significantly down.
4) A few notes: the plumbing set up is very important. Look at it before you start. The foundation has to be 12 inches deep at least. If it is 6 inches deep they will have you do some re foundation work. Luckily mine was 12 inches already. I ended up doing vaulted ceiling, which was a nice touch. The electricity was a pain, because my panel was at the front of the house and had to run it all the way to the back of the house. The whole project should take about 10 weeks to finish up. The rain is not helping.
If you have any specific questions let me know, I am happy to answer to the best of my knowledge.