We are going to buy a lot to build an office building on it. Existings are 3 big ?

What are the procedures from testing the soil to building the building?

How do we do phase 1 environmental report? Do you know a company who in an expert in this in los angeles, California?

Existing on the lot are: 3 big trees, remains of foundation of a duples, and some dubries.

How do we know if there is a septic tank?

This is the first time we are building please let us know all the datails, we appreciate a quick respond.

Thanks a lot

The first step you should consider when planning a construction project is finding and hiring either a licensed architect or structural/civil engineer. Either of these professional disciplines will be able to provide the services either directly or by an associated/sub-contracted services. There are a whole bunch of zoning, building and public works requirements that must be fulfilled before you can even apply for a permit to start construction.

It's a huge job and is usually a huge "headache". You can do it though. Good luck.

Basically the construction engineer working with the contractor you are planing on using will inspect it. Get with the building inspector also and find what his requirements will be.
Normally for the environmental inspection you will get and hire an environmental engineering company to do this.

And you should not buy it without it passing inspectin, make the purchase dependent upon passing these inspections.
A septic tank should be on the county records, there is a office that inspects and approves all tanks.