Cost by height and length
Price follows the area of the wall face (length × exposed height), because taller walls need more block or concrete, a bigger footing, more drain rock and often geogrid. HomeGuide’s national figures for a 50-foot run:
| Wall (50 ft long) | Face area | Typical cost | Permit in Walnut Creek? |
|---|---|---|---|
| 2 ft tall | 100 sq ft | $3,500–$6,500+ | Usually not, unless it holds a surcharge |
| 4 ft tall | 200 sq ft | $7,000–$13,000+ | Often yes: 4 ft is measured from the bottom of the footing |
| 6 ft tall | 300 sq ft | $10,500–$19,500+ | Yes, plus an engineered design |
Angi’s San Francisco-area data runs higher at the top end, $60–$550+ per linear foot, reflecting taller walls, tough soils and Bay Area labor (Angi).
Have a length and height in mind? Get a number for your wall.
Cost by material
| Material | Angi, SF (per sq ft) | HomeGuide, US (per sq ft) |
|---|---|---|
| Poured concrete | $45–$75+ | $20–$45+ |
| Natural stone / boulder | $30–$150+ | $20–$95+ |
| Timber | $20–$45+ | $15–$30+ |
| Gabion | $15–$60+ | n/a |
| Concrete block (segmental or CMU) | n/a | $15–$40+ |
The materials comparison covers lifespan and engineering needs, which matter as much as the price per foot.
Worked examples
Garden wall · 30 ft × 3 ft
90 sq ft × $35–$65+ = $3,150–$5,850+
Low wall on level ground, no surcharge. In Walnut Creek, check whether the buried footing takes total height past 4 ft.
Backyard wall · 50 ft × 4 ft
200 sq ft × $35–$65+ = $7,000–$13,000+
Add permit and engineering if over the threshold: engineers run $500–$2,000+, permits $50–$450+ (HomeGuide national figures; Walnut Creek fees vary by valuation).
Hillside replacement · 50 ft × 6 ft
300 sq ft × $35–$65+ = $10,500–$19,500+
+ engineering $500–$2,000+
+ remove old wall 50 ft × $30–$45+ = $1,500–$2,250+
= about $12,500–$23,750+
Before permit fees, a soils report, drainage excavation or hand-carrying materials on a steep lot.
Add-ons that change the total
| Item | Typical cost | When it applies |
|---|---|---|
| Old wall demolition | $30–$45+ per ft | Replacing timber, block or concrete |
| Drainage excavation | $90–$105+ per ft | Fixing a wall that failed from water |
| French drain / pipe | $10–$85+ per ft | New drain line behind or above the wall |
| Engineering | $500–$2,000+ | Walls over the permit line or with surcharge |
| Permits | $50–$450+ | National range; local fees follow project valuation |
| Soils report | Quoted by a geotechnical engineer | Tiered walls and poor soils in Walnut Creek |
| Hillside access | Quoted per site | Hand-carrying block, small equipment, staging |
Reality check from local permit records
Permit valuations are the figures owners or contractors list on a permit application, so they are rough, but they show the local spread. Recent examples in public permit records include a $48,000 rear-yard retaining wall in Walnut Creek and a $7,000 6-foot CMU wall replacing a wood wall in Danville (County permit records).
Replacing an old wall? A contractor can price demolition and the new wall together.
How to compare quotes
- Height measured the same way in every bid (exposed height vs. bottom of footing).
- Footing size and depth, and whether the wall sits on native soil or fill.
- Drainage spec: drain rock depth, pipe size and where it outlets.
- Who pulls the permit and pays for engineering and a soils report.
- Demolition, haul-off and access (hand-carry, small equipment) itemized.
- Warranty terms in writing, and a deposit within California’s limit.
More on reading a bid in hiring a retaining wall contractor.
Common questions
How much does a 4 ft retaining wall cost?
At HomeGuide’s $35–$65+ per square foot of wall face, each running foot of a 4-foot wall works out to about $140–$260+. A 50-foot run comes to $7,000–$13,000+. In Walnut Creek a 4-foot exposed wall usually exceeds 4 feet once the buried footing is counted, so add engineering and permit costs.
How much does a 20 ft retaining wall cost?
A 20-foot-long, 3-foot-tall garden wall is about 60 square feet of face: roughly $2,100–$3,900+ at $35–$65+ per square foot. Many contractors have a project minimum of $1,500–$3,000+ (HomeGuide), so short walls cost more per foot.
How much does a 5 × 30 ft retaining wall cost?
A 30-foot wall 5 feet tall is 150 square feet of face, or about $5,250–$9,750+ before engineering, permits, demolition and drainage extras. At 5 feet it is over the Walnut Creek and County permit thresholds.
How much does a 100 ft retaining wall cost?
A 100-foot wall 4 feet tall is 400 square feet of face: roughly $14,000–$26,000+ at HomeGuide’s per-square-foot rate. Long walls sometimes price a little lower per foot because setup is spread over more length; hillside access works the other way.
Sources
- Angi: Retaining wall cost in San Francisco (updated Feb 2026)
- HomeGuide: Retaining wall cost (2026)
- City of Walnut Creek: Retaining walls
- Contra Costa County ePermits (permit records)
Checked October 2026. Rules and prices change; confirm with the agency or a contractor before you build.