Tri-Cities Paver Patio Guide: Climate, Permits (2026)

Updated October 19, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.

Quick reference

Topic	What to know	Source
Climate	Kennewick is semi-arid, with 7.87 in. of precipitation a year, July mean highs of 91.3°F and January mean lows of 29.6°F	Wikipedia (NOAA data)
Frost line	24 inches; severe weathering; air freezing index 801	City of Kennewick Building Safety
Call before you dig	Request locates at least 2 business days ahead; homeowners included; owners of noncommercial property may dig under 12 in. without a locate	WA Utilities and Transportation Commission
Right-of-way work in Kennewick	Separate permit required; bonded contractors only; driveway entrances and sidewalks inspected before concrete	City of Kennewick
Contractor registration	All construction contractors register with L&I; bond of $30,000 (general) or $15,000 (specialty)	WA L&I
Summer water	Richland's summer water use rises almost five-fold	City of Richland Water Operations

How does the Tri-Cities climate affect pavers?

It's hard on hardscaping in two directions. Kennewick has a semi-arid climate that borders on desert, averaging 7.87 inches of precipitation a year, with July mean highs of 91.3°F and record highs of 115°F. In winter, January mean lows sit just below freezing. Richland and Pasco are similar, at roughly 7 inches of precipitation a year in the rain shadow of the Cascades. That combination of baking summers, freezing nights and irrigated yards means the ground under a patio expands, contracts, dries and gets wet over and over.

Interlocking pavers on a compacted gravel base handle that movement well because each unit can shift slightly without cracking, and a low spot can be lifted and reset. The base is what really matters: a thin or poorly compacted base is the most common reason pavers sink or rut.

What does the 24-inch frost line mean for my patio?

The City of Kennewick's climatic and geographic design criteria list a frost line depth of 24 inches, a severe weathering rating and an air freezing index of 801. Frost depth matters most for footings, such as pergola posts, covered patio columns and mortared walls, which need to sit below it. A paver patio is a flexible surface and isn't built on frost footings, but the severe weathering rating is a good reason to choose pavers made for freeze-thaw exposure and to keep water from pooling on or under the patio.

What about wind and dust?

Average annual wind speed in Kennewick is about 8 mph, strong winds are common, and dust storms are most frequent in spring and fall when farm soil is exposed. Blowing dust settles into paver joints and gives weeds a place to grow. Polymeric joint sand, which hardens after it's wetted, and periodic sweeping help. Shade structures and fire features should be planned and anchored with wind in mind.

Do I have to call 811 before a paver project?

Yes, in almost every case. Washington's dig law requires anyone digging to request a free utility locate at least two business days before starting, and the state Utilities and Transportation Commission says homeowners must follow the law. Owners or occupants of noncommercial property may dig less than 12 inches deep without a locate, but that exemption covers the owner, not a hired contractor, and excavators must outline the dig area in white paint before calling. You can call 811 or request a locate at callbeforeyoudig.org.

Do I need a permit for a paver driveway or patio?

A patio inside your own lot often doesn't, but check. In Kennewick, a separate permit is required for all work within the public right-of-way, only bonded contractors may work there, and the city requires sidewalks and driveway entrances to be inspected after forming and before concrete is placed. If your driveway project reaches the approach or sidewalk, plan for that permit and ask whether the city allows pavers in that section. Covered patios, pergolas, larger walls and gas lines can also need permits. Richland, Pasco and West Richland run their own permit offices, so check with the city where you live.

How do I check a contractor in Washington?

Washington requires all construction contractors to register with the Department of Labor & Industries. Registered contractors must carry a surety bond of $30,000 for general contractors or $15,000 for specialty contractors, plus general liability insurance of $200,000 public liability and $50,000 property damage, or $250,000 combined. They must include their registration number on business cards, ads, estimates and bids. You can look up any contractor with L&I's Verify a Contractor tool.

Can pavers help with water use?

They can reduce it. Richland's water operations office says summer water consumption rises almost five-fold and that drip or soaker irrigation can save up to 60 percent compared with other methods. Replacing part of a lawn with a patio and drip-watered planting beds is one of the simplest ways to cut outdoor watering.

Questions to ask a contractor

What's your L&I registration number?
How deep will the base be, and how will it be compacted?
What edge restraint will you use?
Which way will water drain off the surface?
Who calls 811, and who pulls any city permit?
What does your warranty cover, and for how long?

Common questions

Do I need to call 811 before a patio project in Washington?

Yes. Request a locate at least two business days before digging. Homeowners are covered by the law, with a narrow exemption for owners digging under 12 inches.

Does a paver contractor need to be registered in Washington?

Yes. Construction contractors must register with L&I and carry a bond and liability insurance. Check them on L&I's Verify a Contractor tool.

Do I need a permit for a paver driveway in Kennewick?

Work in the public right-of-way, such as the approach and sidewalk, needs a separate city permit and a bonded contractor. Check with the city for the rest of the project.

Tri-Cities paver patio guide (2026)