Book it
- Kubota U27-4R1 Mini ExcavatorTight-tail-swing mini excavatorFrom $335/dayBook the Kubota U27-4R1 Mini Excavator
- 7x14 Dump TrailerHaul dirt, gravel and debrisFrom $155/dayBook the 7x14 Dump Trailer
Free pickup in Pierce County; exact location sent after booking. Delivery is $200 each way; your job-site address is checked at checkout.
When a mini excavator makes sense for a wall
Our listing names trenching, drainage, footings and grading among the jobs the Kubota U27-4 is good for. Jobs that fit:
- Cutting the base trench: A straight, even trench for the footing or base, sized to your wall plan.
- Benching into a slope: Cut the hillside back in level steps to make room for the wall and its backfill.
- Moving base rock and drain rock: Scoop rock from the pile and set it where the wall needs it.
- Backfill and cleanup: Push soil back behind the wall with the blade and rough-grade above it.
- Tearing out an old wall: Pull rotted timbers or tipped blocks and load them into the dump trailer.
Footing size, base depth, drain pipe and compaction come from your wall maker’s instructions, or the engineer’s plans if your wall needs a permit.
Plan the wall first
Height decides the permit
Pierce County’s retaining wall technical bulletin (PDF) covers residential walls in unincorporated Pierce County:
- No permit: walls up to 4 feet tall without a surcharge, and walls up to 2 feet tall that support a surcharge.
- Permit required: walls over 4 feet, and walls over 2 feet that support a surcharge. These need site-specific plans by a WA State Registered Engineer.
- Height is measured from the bottom of the footing to the top of the wall.
- All retaining walls must be properly drained (International Residential Code, Section R404.4).
What is a surcharge? Bonney Lake’s retaining wall checklist (PDF) gives terraced walls, buildings, roadways and driveways as examples. The county’s Work Exempt from Building Permit guide (PDF) says exempt work must still meet code.
Count the dirt you move
- Pierce County’s Fill and Grade page requires a permit for grading over one cubic yard in critical areas, or over 50 cubic yards elsewhere.
- Its site development FAQ counts removal, deposit or displacement, so cut, base rock and backfill all add up. Near either line, check with Pierce County Planning & Public Works.
In a city
- Puyallup: the city’s building permit page says retaining walls over 4 feet from the base of the footing, or retaining a surcharge, need a building permit.
- Bonney Lake: the city’s Civil & Utility Permits page requires a permit for any retaining or landscape wall four feet or taller, or any wall supporting a surcharge. New private walls are prohibited in the city’s right-of-way.
- Other cities set their own rules, so check with your city. Area pages: Puyallup · Bonney Lake · Sumner · Auburn · Enumclaw.
Request a utility locate
- WA 811 says to contact 811 at least two, but no more than ten, business days before you start.
- Mark the wall line in white paint first (“whitelining”).
- Private lines, like power to an outbuilding or septic systems, are not marked. WA 811 suggests a private locator. Find your own drain lines too.
Summaries for planning only; follow the official text on each linked page.
Digging with the Kubota U27-4
The Kubota U27-4 is a tight-tail-swing mini excavator. Kubota lists its overall width and its blade width as 4 ft 11 in (Kubota U27-4 brochure, PDF).
- Measure your narrowest gate or path, including posts and hinges, before you book.
- Set stakes and a string line for the wall face, then dig to the line.
- Load spoil straight into the trailer, or pile it away from the trench.
Rules for crews in deep cuts
L&I’s excavation rules apply to employers. WAC 296-155-657 says employees in an excavation must be protected from cave-ins by a protective system, unless it is in stable rock, or less than 4 feet deep and a competent person sees no sign of a cave-in. WAC 296-155-655 says to keep spoil and equipment at least two feet from the edge, or use retaining devices.
Size and booking details: mini excavator guide.
Haul rock in and spoil out
The 7x14 dump trailer brings base rock and drain rock in and takes spoil and old wall material out. Please return it emptied and swept.
- Extra dirt? Pierce County’s Dirt page lists places that take clean fill dirt (no sod or debris). Contaminated soil needs a Waste Disposal Authorization from the Tacoma-Pierce County Health Department.
- Secure every load so nothing drops, sifts, leaks or escapes. Cover dirt, sand or gravel on paved roads unless you keep six inches of freeboard in the bed (RCW 46.61.655).
Towing checks: dump trailer guide. Old timbers or broken block? See the debris guide.
Day, weekend or week?
Mini excavator: At the day rate, 3 days is $1,005 and 4 days is $1,340, vs $1,050 for a week. The weekend rate is $490 (Friday 9 AM pickup to Monday 3 PM return).
7x14 dump trailer: At the day rate, 3 days is $465 and 4 days is $620, vs $575 for a week. The weekend rate is $200 (Friday 9 AM pickup to Monday 3 PM return).
Prices are before WA sales tax and the 1.25% heavy equipment rental tax where it applies. Your exact total shows at checkout.
Questions
Can a mini excavator dig a retaining wall base?
Yes. Our listing names trenching, drainage, footings and grading among the jobs the Kubota U27-4 is good for, and it has a backfill blade. The 7x14 dump trailer brings base rock in and hauls spoil out.
Do I need a permit for a retaining wall in Pierce County?
Pierce County's retaining wall bulletin says walls over 4 feet, or over 2 feet that support a surcharge, need a permit and plans designed by a WA State Registered Engineer. In a city, check with your city.
How is retaining wall height measured?
Pierce County measures from the bottom of the footing to the top of the wall, so the buried part counts. A wall that shows less than 4 feet above ground can still be over the line.
Do I need to call 811 before digging a landscape wall?
Yes. WA 811 says to contact 811 at least two, but no more than ten, business days before you dig. Private lines, like power to an outbuilding or a septic system, are not marked.
How much does it cost?
The mini excavator is $335 a day, $490 a weekend or $1,050 a week. The 7x14 dump trailer is $155 a day or $575 a week. Prices are before WA sales tax and the 1.25% heavy equipment rental tax where it applies. Your exact total shows at checkout.
More guides: all rental guides. Water pooling behind the wall? See the drainage guide. Leveling above the wall? See the grading guide. Which guide fits your job? Holes for deck or shed footings, not a wall base: footing excavation guide.