Why Zoning Is Something You Must Understand?

Whether you’re house hunting, planning an addition, or evaluating a property as an investment, there is one step you should never skip:

Check the zoning first.

Zoning directly impacts what you can build, how you can use a property, and ultimately its long-term value. Many costly lessons could have been avoided with an early zoning review.

What Is Zoning?

Zoning is a form of land-use regulation that defines how a property can be used and developed. Common zoning categories include (but are not limited to):

1. Residential (R Zones)

• R1 – Single-family residential

• R2 – One- and two-family residential

• R3 – Multi-family residential

• R4 – High-density multi-family residential

⚠️ Why the exact “R” designation matters

• Recent discussions around SB9 (duplexes and lot splits) apply only to R1 properties

• ADUs are now allowed in multi-family zones, but:

  • The number of ADUs

  • The maximum size

  vary significantly between R1, R3, and other residential zones.

• PD – Planned Development (PD) Zones
  PD zoning does not mean additions are prohibited. However, PD properties follow their own customized development standards, which must be reviewed carefully on a case-by-case basis.

2. Commercial (C Zones)

Commercial zoning includes categories such as Commercial-Service and others, each with its own regulations.

⚠️ A real-world case worth sharing

We recently reviewed a property that looked like a typical single-family home:

• Detached house

• Individual lot

• Residential appearance

However, zoning research revealed it was actually located in a Commercial (C) zone.

This made the property a legal nonconforming use, often referred to as being “grandfathered.”

What does that mean?

• The house was legally built before zoning regulations changed

• As long as the owner does nothing, the property can continue to be used as a residence

• Once you attempt an addition or remodel, strict limitations apply:

  • ADUs are not allowed

  • Even minor alterations may trigger a public hearing

  • Expansion opportunities become extremely limited

If a buyer had known this during the purchase phase, it would very likely have been a deal breaker.

Final Takeaway

Be proactive.
Always check zoning— even if you’re just shopping for a house.

Understanding zoning early can:

• Prevent costly surprises

• Protect your investment

• Reveal (or limit) future development potential

At TLArchitects, zoning analysis is a critical first step in every project—because good design starts with knowing the rules.