# Retaining Walls in Temecula

> Retaining walls in Temecula: the city's CD-25 block standard, drainage behind the wall, surcharge and engineering limits, geogrid block walls and fences on top.

URL: https://caskfencetemecula.com/retaining-wall-installation/

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Reinforced block and segmental retaining walls for sloped and terraced lots, with the drainage, footing and engineering each wall needs, and fences planned on top.

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Last Updated: October 31, 2026

Height alone doesn't decide how a retaining wall is designed. What sits above it, and where the water goes, matter just as much.

a

open joints in the first course let water out

b

the wall holds back the higher yard

c

slope above the wall adds load

1. **a** open joints in the first course let water out
2. **b** the wall holds back the higher yard
3. **c** slope above the wall adds load

A retaining wall is holding soil and the water in it every day. The parts that keep it standing, the footing key and the drain, are buried once it's done.

[Cask Fence Temecula](https://caskfencetemecula.com/) plans and manages retaining wall installation for sloped and terraced lots in Temecula and the nearby cities, with each wall carried out by licensed and insured contractors holding the license class the wall needs: C-29 for block and segmental walls, C-8 for poured concrete. A lot of Temecula’s tract back yards end at a manufactured slope or sit higher than the neighbor, and a retaining wall is what turns that grade into usable yard. It is also where fencing meets structure, because the fence often goes on top. If a wall only divides two level yards, the [block wall page](https://caskfencetemecula.com/block-wall-installation/) is the right place to start.

## When a wall becomes a retaining wall

The line is drawn by the city’s own block wall standard: a freestanding wall can have no more than 6 inches of grade difference across it. Past that, the wall is holding soil back, and it has to be designed for the push of that soil and the water in it. A decorative garden wall and a retaining wall can look identical from the yard, but the retaining wall has a wider footing, more steel, every cell grouted and a drain behind it.

## Temecula’s standard retaining wall, CD-25

The City of Temecula publishes a pre-engineered design, CD-25, for reinforced concrete block retaining walls up to 6 feet tall. Like the freestanding wall standard, it comes from the Western Riverside County Code Uniformity Program, and [Murrieta](https://caskfencetemecula.com/service-areas/murrieta/) and Riverside County use matching tables. It covers walls with level ground behind them and walls holding a slope no steeper than 2:1.

That slope makes a big difference. The standard designs for 30 pounds per square foot of equivalent soil pressure with level backfill and 43 with a 2:1 slope behind, and the footing grows to match. For a toe-type footing:

| Wall height | Level backfill | 2:1 sloping backfill |
| --- | --- | --- |
| Up to 3 ft | 21 in. wide, no key | 18 in. wide, 8 in. key |
| 3 ft 1 in. to 4 ft | 24 in. wide, 5 in. key | 30 in. wide, 16 in. key |
| 4 ft 1 in. to 5 ft | 36 in. wide, 7 in. key | 48 in. wide, 25 in. key |
| 5 ft 1 in. to 6 ft | 45 in. wide, 8 in. key | 69 in. wide, 30 in. key |

A 6-foot wall holding a slope needs a footing close to 6 feet wide with a 30-inch key below it. That is a lot of excavation, often into the slope you’re trying to hold, and it’s why the slope above a wall moves its price as much as its height does. The standard also allows a heel-type footing with different dimensions for sites where a toe can’t extend in front of the wall.

## Solid grout, mortar and steel

Every cell in a CD-25 retaining wall is grouted with 2,000 psi portland cement grout, unlike a freestanding wall where only the steel cells are filled. Mortar between the blocks is Type M or S, footing concrete is 2,500 psi, block meets ASTM C-90 grade N, and rebar is grade 40 with laps of at least 40 bar diameters. Walls between 5 and 6 feet use 12-inch block for the lowest 24 inches, where the soil pressure is highest. Where a grout pour runs over 5 feet, cleanouts at the bottom course let the inspector see the bars and let debris be cleared, so the grout bonds at the base.

Mortar and grout aren’t interchangeable here. Mortar sets the blocks; grout makes the block, steel and footing act as one piece.

## Drainage behind the wall

A retaining wall that can’t drain is holding back mud, and saturated soil pushes far harder than dry soil. CD-25 sets a minimum: either one cubic foot of clean coarse gravel per foot of wall with a 4-inch perforated pipe sloped at 1% to an outlet, or open head joints in the first course so water can weep through. In Riverside County tracts, the county’s version of the standard doesn’t allow the open-joint option, so the gravel and pipe are required. The drain is inspected before grout, so you can see it before it’s buried.

Temecula is dry most of the year, which lulls people. The city’s design rainfall is 3 inches an hour, and winter storms can soak a slope in a day. In places a cemented hardpan sits a couple of feet down and slows water from soaking away, so water can perch behind a wall. A pipe with no outlet, weeps buried under mulch or soil, or gravel clogged with fines all let pressure build.

The back face of a block retaining wall is wet by design. The standard lists a moisture barrier on the soil side as optional, and without one, white efflorescence on the yard face is expected rather than a sign of failure.

## Surcharge: driveways, pools, slopes and walls above

A surcharge is any load on the soil behind a wall beyond the soil itself: a driveway or RV pad, a pool, a house or garage footing, another wall above, or a fence. CD-25 states plainly that it is not designed for surcharge from vehicles or other structures, so walls in those spots go to an engineered design. Tiered walls are the same: the standard has no terraced detail, and the upper wall loads the lower one. A fence that steps down beside terraced walls follows the patterns in the [stepped vs racked guide](https://caskfencetemecula.com/guide/stepped-vs-racked-fence/). Walls under a slope steeper than 2:1 also fall outside it.

The 2025 California Residential Code draws the engineering line in two places. Section R404.4 requires an engineered design for walls not braced at the top that retain more than 48 inches of unbalanced fill, and for walls over 24 inches tall that resist loads in addition to soil. And any footing near a descending slope must keep at least 5 feet of soil to the slope face, so a wall at the top of a tract slope may need to sit back from the edge or go deeper. The [hillside fence page](https://caskfencetemecula.com/hillside-fence-installation/) covers those slope-edge lots.

## Permits and when an engineer is needed

The state baseline in CRC R105.2 exempts retaining walls not over 4 feet, measured from the bottom of the footing to the top of the wall, unless the wall supports a surcharge. Because the footing is buried, a wall showing about 3 feet above grade can already be past that line. Temecula Building & Safety decides whether your wall needs a permit, a planned community’s association may need to approve it first (see the [HOA approval guide](https://caskfencetemecula.com/guide/hoa-fence-approval/)), and the [height and permit rules guide](https://caskfencetemecula.com/guide/temecula-fence-height-permit-rules/) covers the overlap with fence rules.

The City of Temecula’s fee schedule prices retaining walls per 50 linear feet. A wall built to the city standard is $248 for up to 50 feet ($90 plan check plus $158 inspection) and $30 for each additional 50. An engineered wall up to 8 feet is $357 for the first 50 feet, or $471 over 8 feet, with $140 for each additional 50 feet either way. Engineering design fees are separate, and these are city fees, not project prices. Unincorporated addresses such as [French Valley](https://caskfencetemecula.com/service-areas/french-valley/) go to Riverside County Building & Safety.

When a permit applies, CD-25 lists three inspections: footing, with steel held 3 inches off the soil; rebar, pre-grout and drainage; and final, after grout and backfill and before any cap.

## A privacy wall on top of a 2-foot retaining wall

The most common tract condition is a neighbor’s yard up to 2 feet higher, with a privacy wall wanted on top. CD-25 has a detail for exactly that: a retaining portion of up to 2 feet, solid grouted with open head joints at the bottom for drainage and two #4 bars in a bond beam at its top, then up to 6 feet of freestanding block above, grouted only at the steel. Anything retaining more than 2 feet under a privacy wall goes to the full retaining table or an engineer.

How tall the combined wall and fence may be is a zoning question. Codes differ on which side of the wall the height is measured from, so the combined height is confirmed for your address. [Lake Elsinore](https://caskfencetemecula.com/service-areas/lake-elsinore/), for example, measures from the highest grade on either side. On a segmental wall, the manufacturer guidance sets fence posts and railings at least 3 feet behind the top course, or in sleeves designed into the wall, so post holes don’t break into the reinforced soil. A light open fence such as [wrought iron](https://caskfencetemecula.com/wrought-iron-fence-installation/) or a [vinyl](https://caskfencetemecula.com/vinyl-fence-installation/) fence on its own posts behind the wall puts less load on it than solid panels.

## Segmental block walls with geogrid

Segmental retaining walls use dry-stacked concrete units from makers such as Allan Block and MagnumStone. Short walls rely on the weight and setback of the units. Taller ones add geogrid: layers of polymer grid laid between courses and out into the backfill, so the wall and a block of soil behind it act as one mass.

The parts that make it work are invisible later. The first course sits below grade on a leveling pad of compacted crushed base. Clean drain rock goes directly behind the units with a perforated pipe to an outlet. Backfill goes in thin lifts, no more than 8 inches, compacted to a tested density, with only hand compactors close to the wall. Grid lengths come from the engineer’s cross-section, not a rule of thumb, and the excavation behind the wall has to be about as deep as the grid is long. On a tight side yard, that work zone can decide whether a geogrid wall is possible at all. CSLB’s C-29 class covers masonry units installed with or without mortar, so segmental walls are masonry work too.

## Why retaining walls fail, and repair or rebuild

The usual causes are water and load: a drain that never worked or clogged, weeps buried in soil, a footing too small for the slope behind it, a driveway or pool added above a wall that wasn’t designed for it, or soil that moves. Soil survey data for [Canyon Lake](https://caskfencetemecula.com/service-areas/canyon-lake/) shows high shrink-swell clay, which swells when wet and shrinks when dry and pushes on walls differently through the year.

A crack or lean shows that something moved, not necessarily why, and more than one cause can be at work. A wall that leans because its support zone failed can’t be pushed back and patched on its face; the soil and drainage behind it have to be rebuilt. Isolated issues, such as a clogged outlet or a broken cap, can be repairs, and the [fence repair assessment](https://caskfencetemecula.com/tools/fence-repair-assessment/) helps sort out a fence that sits on the wall. Sorting one from the other starts with looking at the drain, the backfill and what sits above. For hillside soil and post questions, the [fence posts and soil guide](https://caskfencetemecula.com/guide/fence-posts-temecula-soil/) also applies.

## What sets the price of a retaining wall

Retaining walls are priced per project. The drivers are height, length and face area, the slope or surcharge behind the wall, footing and key size, wall type, how much excavation and whether it hits hardpan or rock, drainage, geogrid length and the work zone it needs, imported backfill, access for equipment and block, engineering and soils reports, the permit and inspections, demolition of an old wall, and any fence or railing on top. The [fence cost guide](https://caskfencetemecula.com/guide/fence-cost-temecula/) explains how wall pricing works, and the [property line survey guide](https://caskfencetemecula.com/guide/property-line-survey-fence/) helps where the wall sits on a shared line. For a written scope, [send the details](https://caskfencetemecula.com/contact/).

## What's included

- Walking the slope with you: wall height, what sits above and below, drainage paths and access
- Deciding whether the wall fits the city or county standard, or needs an engineer
- A written scope naming wall type, height, footing, drainage, backfill and any fence on top
- Permit application and the three inspections when the wall needs a permit
- A DigAlert ticket before excavation
- Excavation, footing and key, with steel inspected before concrete
- Drain gravel and pipe, or open weep joints, inspected before grout
- Block laid and solid grouted, or segmental units placed with geogrid and compacted backfill
- Backfill, cleanup and haul-away of excess soil

## Reinforced block (CD-25) or segmental block with geogrid

|  | Reinforced concrete block | Segmental block, gravity | Segmental block with geogrid |
| --- | --- | --- | --- |
| How it holds soil | Steel and grout in a cantilevered wall on a footing | Weight and setback of stacked units | Units plus layers of grid that lock a block of soil together |
| Space it needs behind | Footing heel or toe width, plus drain gravel | Little beyond drain gravel | A work zone about as deep as the grid is long |
| City standard available | Yes, CD-25 up to 6 ft without surcharge | No; manufacturer design and Building & Safety review | No; engineered section |
| Fence on top | Privacy wall atop a 2 ft retaining wall has a city detail | Posts set back from the face | Posts set back from the top course or in designed sleeves |
| Contractor class | C-29 masonry | C-29 masonry | C-29 masonry |

## Related resources

Learn

What are the fence height rules in Temecula?

Height is decided in more than one office. Here is which rule applies to a fence, a block wall, a retaining wall or a pool barrier, and what each one actually says.

Decision Guide

Stepped vs. racked fence: which works on a sloped yard?

A fence can follow a slope by tilting with it or by dropping in level steps. The grade, the material and what the fence has to keep in decide which.

Learn

How deep should fence posts go in Temecula soil?

Why fences lean, what the auger hits under Temecula-area lots, and how height, wind and the fence system decide how deep and how wide a post footing has to be.

Decision Guide

Do you need a survey for a fence?

How to tell whether the corner pins and the recorded map are enough to set a fence line, and when a licensed land surveyor is the cheaper answer in the long run.

Learn

How does California's good neighbor fence law work?

Civil Code 841 read line by line: who it covers, what the notice has to contain, how a neighbor can rebut an even split, and the questions it leaves for a surveyor or an attorney.

Cost Guide

How much does fence installation cost in Temecula?

Per-foot budgeting ranges for every common fence, the local conditions that push a Temecula job up or down, and the public figures that sit inside the price.

## From the first call to the last latch

1. The call Length, material, height, slope, how many gates, and anything the HOA has already said.
2. The site visit Walk the line, look for corner pins or a survey, and check grade, rock, drainage and access for equipment.
3. Paperwork HOA submittal, written notice to a neighbor where a fence is shared, any permit, and a DigAlert ticket at least two working days before digging.
4. The build Posts set and the concrete cured, then rails and boards or panels, then gates hung and adjusted on their own heavier posts.
5. The walk Check plumb and line, gate swing and latch, and the gap at the bottom, then clear debris and leftover concrete.

## What this work looks like

Footing trench at the base of a slope with a rebar grid and vertical dowels.

Perforated drain pipe and gravel backfill behind a partly built block retaining wall.

Close view of an open weep joint in the bottom course of a block retaining wall above a gravel strip.

Two terraced block retaining walls with a planted terrace between them on a hillside lot.

Before

After

## Retaining Walls questions

### Does a 3-foot retaining wall need a permit in Temecula?

It might. The state baseline exempts retaining walls not over 4 feet, but that height is measured from the bottom of the footing, so a wall showing 3 feet above grade with a buried footing can already be over 4 feet. Any surcharge, such as a slope, driveway or structure above it, removes the exemption. Temecula Building & Safety decides for your address; unincorporated areas go to Riverside County.

### Why is the bottom row of my retaining wall missing mortar between blocks?

That is usually on purpose. Temecula's retaining wall standard allows open head joints in the first course as the drain, instead of a gravel and perforated pipe system. Those gaps let water out from behind the wall so it doesn't build up pressure. Don't fill them with mortar or let soil and mulch bury them; a blocked weep defeats the drain.

### Can two shorter retaining walls replace one tall one?

Sometimes, but not as a way around engineering. An upper wall loads the soil behind the lower wall, and Temecula's standard excludes surcharge from other structures, a wall above included. Terraced walls need enough distance between them, or an engineered design that accounts for the upper wall's load. Height, spacing and soil decide which applies.

### Can I build a retaining wall next to my driveway or pool?

Yes, but not to the city's standard plan. CD-25 is not designed for surcharge loads from vehicles or structures, so a wall that holds up a driveway, an RV pad, a pool deck or a house footing needs an engineered design. The 2025 California Residential Code also calls for engineering once a wall over 24 inches tall carries loads beyond the soil.

## Related services

### Block Walls →

Freestanding concrete block walls and pilasters, in precision, split-face or slumpstone, with wrought iron infill where a view matters, built to the city's standard or an engineered design.

### Hillside Fences →

Fences that step or rack down a slope, gates placed where the grade allows a swing, posts drilled into hardpan or rock, and fences built on or above retaining walls.

### Wrought Iron Fences →

Ornamental tubular steel and aluminum fences and iron gates, on their own posts or between block pilasters, finished to hold up in Temecula sun.