If the soils are good often times it doesn't matter.   

I briefly looked over the Oakland sewer line requirements and it seems materials other then cast iron are allowed unless the line is less that 12" below soil.

I am currently house hacking a Single Family Home in Sandy, Utah (Room Rental Model) but, I want to invest in Multi-Family properties after I graduate in the Spring 2024.

Originally posted by @Sandi Ghobrial:@Michael Myers which areas/ zipcodes you think will rent out quickly in Jacksonville fl? 

Is it a soils issue or something less serious?

However, you need a permit and the town inspects it once the hole is dug, and if there is any smell or visible sign of oil you must stop and bring in another company to take soil samples and dig up all the soil that is contaminated. 

But, it's very very likely you'll have to deal with one or multiple of:Drainage issues that have caused undiscovered damageAge and material of sewer lines and water supplySettlement or expansive soils causing problemsCentral systems (not having sufficient or central heating / ACJust some examples. 

Soil settlement caused foundation movement and cracking which took about a week to repair between foundation company, carpenters and painters.

When Sandy happened my basement was flooded completely. try looking into East New York.

During inspection, we discovered there is an abandoned oil tank and soil contamination.