Retaining Walls and Rock Walls in Pend Oreille County

Whether a retaining wall needs a permit under the International Building Code depends on its height, measured from the bottom of the footing to the top of the wall, and on whether it carries a surcharge such as a slope or a building. Walls not over four feet are exempt unless they carry one.

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What a retaining wall or rock wall is

A retaining wall holds back soil where the ground changes level. A rock wall, also called a rockery, stacks large rocks to protect a slope from slipping or eroding. On rural lots in Pend Oreille County these walls hold up driveway cuts, building pads, shop yards and creek banks, and they are built with the same excavation equipment as the rest of the site work.

The excavation comes first and matters most. The wall needs a trench or footing dug to the planned depth on firm ground, backfill that drains, and a way for water behind the wall to get out. Walls fail when water builds up behind them, so drainage is part of the wall rather than an add-on.

A City of Covington, Washington, bulletin separates wall types in a way that is useful here: cantilever walls of reinforced concrete or masonry, segmental walls made of stacked concrete units, and rock walls of un-cemented stone. It notes that rock walls are gravity walls and are not structural, which is why they are usually used for slope stability and erosion control.

When people look into this

A driveway or pad is cut into a hillside and the cut face needs support.
A slope behind a shop or house is eroding.
A creek bank or ditch needs protection.
A yard needs to be leveled into terraces.
A previous wall has leaned, bulged or washed out.
A building is planned close to a drop in grade.

What the work usually looks like

Define the wall. Height, length, what it holds back and what sits on top of the retained soil.
Check permits. Ask the county whether the wall needs a permit and an engineered design.
Locate utilities. 811 notice comes first (details below).
Dig the footing. The trench is dug to the planned depth on firm ground.
Build and backfill. The wall is built and backfilled with material that drains.
Plan the water. A drain and outlet keep water from building up behind the wall.

How to prepare

Before work starts, it helps to settle these points:

Measure how tall the wall will be from the bottom of the footing to the top.
Note what sits above the wall: a slope, a driveway, a building or a fence.
Ask the county whether a permit or an engineered design is needed.
Mark property lines so the wall and its footing stay on your land.
Show where water runs on the slope above and around the wall.
Find out who will call 811 and get the ticket number.
Get the type of wall, the materials and what is included in writing.

What affects the cost

Excavation is commonly priced by the hour for operator and machine, or as a set price for a defined scope. For a wall, height and length drive the total, and the type of wall changes it a lot.

Height and length. Taller and longer walls need more material and a deeper footing.
Wall type. Rock, segmental units and reinforced concrete have very different material and labor needs.
Engineering. A wall that needs an engineered design adds that cost.
Drainage. Drain rock, pipe and an outlet add material and time.
Access. Heavy rock and units must reach the site.
Soil and slope. Soft ground or a steep slope changes the dig.
Removing an old wall. Tearing out and hauling a failed wall adds work.

Height is measured from the bottom of the footing

The most common misunderstanding about the four-foot rule is which height counts. The bulletin explains that the height in the code is measured from the bottom of the footing to the top of the wall, not just the visible face. A wall that shows three feet above ground can be four feet or more by this measure once the footing depth is included.

That is why the description you give the county matters. Give the total height from the bottom of the footing, say what the wall holds back and what sits on top of the slope, and ask for the answer in writing. If an engineered design is needed, ask the company pricing the work whether it is in the price or separate.

Local rules and sources

Permits. The International Building Code, which many local building codes are based on, exempts retaining walls that are not over 4 feet high, measured from the bottom of the footing to the top of the wall, from a building permit unless they support a surcharge such as sloping backfill, a structure or vehicle loads (IBC section 105.2). Local departments can read this differently, so ask the county first. A City of Covington, Washington, bulletin reads the rule as roughly three feet of exposed wall when the footing is about a foot thick, which shows how local reading can differ. For land in Pend Oreille County outside city limits, Pend Oreille County's Community Development Department handles building permitting. Inside a city such as Newport, ask the city.

Utility locates. In Washington, notice must go to the one-number locator service (dial 811) at least two full business days, and no more than ten full business days, before digging starts (RCW 19.122.030). Whoever is digging is responsible for making sure the notice is made, even if someone else makes the call for them.

Excavation safety. Washington's Department of Labor & Industries requires a protective system for every excavation four feet deep or deeper, unless it is made entirely in stable rock, and for shallower excavations when a competent person sees a potential cave-in (WAC 296-155-657). L&I's trenching safety publication adds that digging spoil must stay at least two feet from the edge of the excavation and that workers in a trench four feet or deeper need a way in and out at least every 25 feet.

Registration. Washington contractors are checked on the state Department of Labor & Industries “Verify a Contractor, Tradesperson or Business” page.

Reasons to trust this page

Most rules on this page name their public source, such as a Washington statute or a county office.
Cost factors are explained in plain terms, and this site does not quote prices.
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Common questions

Does a retaining wall need a permit in Pend Oreille County?

The International Building Code exempts retaining walls not over four feet high, measured from the bottom of the footing to the top of the wall, unless they support a surcharge such as a slope, a structure or vehicle loads. Local departments can read it differently, so ask Pend Oreille County's Community Development Department before work starts.

What is a surcharge on a retaining wall?

A surcharge is an added load on the soil the wall holds back. The Covington bulletin lists sloping retained soil, structure footings, adjacent vehicle loads and solid fences attached to the wall as examples. A wall that carries a surcharge loses the four-foot exemption, so describe everything above the wall when you ask the county.

What is the difference between a retaining wall and a rock wall?

The Covington bulletin describes cantilever walls as reinforced concrete or masonry on a footing, segmental walls as stacked concrete units, and rock walls as un-cemented, interlocking rows of large rock that are gravity walls rather than structural walls. Rock walls are usually used for slope stability or erosion control on stable slopes.

Why does water behind a wall matter?

Water that builds up behind a wall adds pressure the wall may not be built to resist, so drainage is part of the design. Ask any company what drain material, pipe and outlet are included, and what happens to water running on the slope above. A wall price that leaves drainage out is not comparable to one that includes it.

How is wall work priced?

Excavation is commonly priced by the hour for operator and machine, or as a set price for a defined scope. For a wall, height, length, wall type and any engineering change the total. Ask for the type of wall, the materials and what is included in writing, so prices from different companies cover the same work.

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