property checklist beginner's guide to adus

Chapter 2: ADU Property Checklist

First, make sure your property is ADU ready.

As we mentioned in Chapter 1, ADUs are more than just four walls. There are a lot of points to make sure your property is ready for an ADU to be built.

In order to build an ADU, you first need to make sure it is possible to even build one on your property. This is arguably the most important piece of the ADU puzzle: If you can’t build an ADU (or it’s not financially feasible), there’s no reason to go any further in this guide.

Property Checklist

Below we have included a screenshot of what to look for when consider building an ADU. We’ll go in depth about each section afterwards, so don’t worry if you aren’t sure what one of the terms mean.

How does an ADU actually get built?

An ADU essentially comes down to four main categories:

  1. Space: Does your property have enough square footage with setbacks to place an ADU comfortably? Will the zoning allow for an ADU? Do you have an entry point for access to your project site? Do you have an easement on your property?
  2. Foundation: What soil is on your property? Rocky, clay? Which foundation type makes sense for your property? Does your climate or geographical location require special treatment (i.e. are you in a flood zone or earthquake prone area?)
  3. Utilities: Will you need to upgrade your panel (most likely – yes)? Where does your plumbing line connect to your home?
  4. Permits: Does your local jurisdiction have special treatments of ADU’s? What is their process to acquiring a permit?


Adding an ADU will occupy space on your property, but you also have to account for property setbacks when adding any type of residential unit. Zoning type is important because your city may not allow you to build on the zone your property falls under (or at least make it extremely complicated). Entry points must be established for any construction project, and if entry to your backyard is too narrow – that may put a halt to a project before it ever starts.

What are Property Setbacks?

Property setbacks are building restrictions imposed on property owners. This could be distances from a curb, property line or structure within which building is prohibited. Basically – it tells you where you can and can’t build something.

What are Zoning Types?

Zoning types and regulations specify whether specific spaces in a jurisdiction (city or county) can be used for a specific purpose. For example: your property will most likely be zoned “Residential”, but there are other types such as: “Agricultural” or “Open Space”. These zones typically coincide with specific regulations for each. Zones are here for good reasons, you wouldn’t want a manufacturing facility built right next to a residential property.

What are Access Points?

Access points (or entry points) – are simply ways to get into the project on your property. Good examples of an access point for an ADU project include a side gate or a rear back-gate. If there ins’t a good access point for an ADU project, typically permission is given by a neighbor to knock down parts of a fence to complete the project – and are rebuilt once the project is completed.

Example Access point for a potential ADU project.

What are Easements?

An easement is a non-possessory right to use and enter onto the property of someone else without owning the property itself. Common examples would include a phone, gas, or power line. In reference to an ADU project – this means you should check with your local planning department first to see if you have any easements you should watch out for before you start digging.


There are plenty of foundation types you can use for an ADU. It really depends on a few factors including the type of soil and your climate/geographical area.

Soil Types

Because we are focusing on ADU’s we’ll focus on the primary soil types you will find in California. We won’t goo to in-depth in this guide, just know that there are four main types of soil: sand, silt, clay and loam. Loam is a combination of the three (sand, silt, and clay) and you will typically find mixtures of them in the soil on your property.

Climate + Geographical Location

If you have a property in California – you will likely have some specific environmental difficulties. Namely, earthquake, fires and possible flood zones in your area. Each of these difficulties may effect your build in someway – it is important to know what these are and to address them with an experienced ADU builder. You can learn what type of difficulties your property may have by entering your address in the Symbium webtool.

Foundation Types

We’ll cover foundations later in the “Construction” chapter – for now just understand that the soil and climate your property has will help determine the appropriate foundation for your project.


There are two primary utilities to worry about when working on an ADU project, electric and plumbing. (Gas is typically not found when working with ADU’s – but of course – it’s a personal choice).


Every home (or building for that matter) will have an electrical connection somewhere. Very simply, power flows from the grid through transporters to your home’s panel. You will most likely need to add a subpanel to your home that takes electricity from your existing home’s panel and directs into your ADU’s panel. Most ADU panels require at least 100A, though this is a rule of thumb.

You should know what amperage is on your current home panel and understand if you’ll need a panel upgrade in order to meet your ADU’s capacity. You can check by contacting your local PG&E or Southern California Edison representative and alerting them of your plans to add an ADU.

If you are renting out your ADU – you will likely want to a submeter on your ADU panel so you know what to charge your tenant. PG&E can install a submeter or you can purchase your own on the open market.


Plumbing system in your home (and an ADU) are composed of two seperate subsystems. One subsystem bring freshwater in, and the other takes waste out. Water in your home comes in under pressure in order for it to travel upstairs or around corners. As it comes in it passes a meter that registers how much you use.

Your drainage system however, does not depend on pressure, gravity will pull the waste along because all drainage pipes pitch downward toward the sewer. The sewer then leads to a sewage treatment facility.

Your ADU will need to either hook into the existing lines of your home or create a new line, typically it will hook into existing lines but your jurisdiction may have specific rules.



It’s essential to know what the ADU procedures are for your jurisdiction, most importantly, are they even allowed?! State guidelines state that ADUs must be allowed on single family homes, but of course, every jurisdiction can pass different legislation that could either stop your project from starting or significantly lengthen the time to build. You can do a quick check on your jursidction’s ADU policies with the Symbium webtool – but should always contact your planning department for the full picture.


Now that you’re property is ready for an ADU, we can get into Chapter 3: Design