Linear Slot Drains and Trench Drains (San Diego 2026): Specs, Costs, Permits, and Discharge
Updated February 2026 – San Diego County
Linear slot drains and trench drains are not decorative upgrades. They are a risk-control system that protects doors, slabs, pool decks, and driveways from ponding, staining, algae, and water intrusion. In premium projects, the drain is only “expensive” when it is done late or done wrong.
This guide explains when to use a slot drain vs a trench drain, how to detail the cross-section so it does not settle or clog, where the water can go, and what to demand in bids.
Educational only (not legal advice). Drainage and discharge requirements vary by jurisdiction (City vs County vs other cities), parcel constraints, and right-of-way conditions. Always confirm your address-specific path.
Linear drains matter most in projects with tight tolerances: doors and thresholds, pool decks, covered patios, and driveway intercept drains.
TL;DR – When Slot Drains Win vs When Trench Drains Win
- Slot drain wins when you want a clean, modern look at doors and along pool decks with minimal visual clutter.
- Trench drain wins when you need higher capture capacity or you are intercepting sheet flow at driveways, garage entries, or long hardscape edges.
- Most failures are not the drain body. Failures are slope mistakes, no cleanouts, no discharge plan, and no concrete collar or structural support so the drain settles.
- Best practice: slope first, drain second. The drain is an insurance policy, not a substitute for grade.
- Value buyer rule: the bid must state drain locations, outlet size, discharge path, and cleanout access. If it does not, it is not included.
Costs: Linear Slot Drains and Trench Drains (San Diego 2026)
These are installed planning ranges for San Diego. Pricing depends on length, excavation depth, concrete collar, outlet piping, and where the discharge can go.
The biggest cost driver is usually the outlet and routing, not the drain itself.
| Drain type | Typical installed range | Best for | What drives cost |
|---|---|---|---|
| Linear slot drain (per LF) | $90–$220/LF | Doors, pool deck edges, modern patios | Concrete collar, outlet size, routing distance, cleanouts |
| Trench drain (per LF) | $120–$280/LF | Driveway intercepts, garage thresholds, high-flow edges | Depth, rebar/concrete collar, grate type, outlet and discharge |
| Outlet piping and discharge routing | Varies widely | Every drain system | Distance, depth, obstacles, lawful outlet, restoration scope |
Adders: Why Drain Quotes Swing
| Adder | Why it matters | How to control it |
|---|---|---|
| Outlet location | The drain is cheap compared to where the water must go | Define discharge path early and put it in writing |
| Depth and base conditions | Deeper excavation and unstable base require better support | Require cross-section and compaction requirements |
| Concrete collar and reinforcement | Prevents settlement and grate rattle | Specify collar width, thickness, and rebar requirements |
| Driveway load rating | Vehicle loads require proper channel rating and support | Specify vehicle-rated system and edge restraint details |
| Cleanouts and maintenance access | No access means future clogs become demolition | Require cleanout locations and access details |
Linear Slot Drain vs Trench Drain: Which One Should You Use?
| Category | Slot drain | Trench drain |
|---|---|---|
| Look | Minimal, modern, nearly invisible | Visible grate (can still be premium) |
| Capture capacity | Moderate | Higher potential for heavy sheet flow |
| Best placement | Doors, pool decks, clean patio transitions | Driveways, garage thresholds, intercept lines |
| Maintenance | Needs access points and periodic flushing | Grate removal access, sediment management |
Specs and Cross-Sections: What to Demand in Writing
Linear drains fail when cross-sections are vague. Elite installs specify the drain body, concrete collar, outlet size, slope intent, and cleanouts.
| Item | What “good” looks like | Red flag |
|---|---|---|
| Slope intent | Flow arrows and low points shown on plan | No slope notes, “as needed” language |
| Concrete collar | Defined support around drain to prevent settlement and rattle | Drain bedded in sand with no structural support |
| Outlet size and cleanouts | Outlet sized and cleanouts accessible | No cleanouts, unclear outlet path |
| Edge finish | Flush transitions and clean sawcut edges where required | Uneven edges and trip lips |
Discharge: Where the Water Can Go
The drain is only half the system. The other half is the discharge path. Most disputes and rework come from drains installed with no defined outlet.
- Define the outlet: where does the water go in a heavy storm.
- Do not create neighbor impacts: uncontrolled discharge is the fastest way to create conflicts.
- Service access: cleanouts and accessible junctions prevent future clogs from becoming demolition.
Deep dive: Drainage & Stormwater (San Diego)
Permits, HOA, and Right-of-Way
Drainage is often “invisible,” but approvals can still apply, especially when you are near the public frontage or tying into public systems.
Elite projects screen this early so design does not change after pricing.
- HOA/DRC: some communities require approval for visible drains at edges and thresholds.
- ROW exposure: driveway aprons, sidewalks, and parkways can trigger right-of-way rules.
- Coastal and older homes: overlays can add review steps for scopes you do not expect.
Related: Driveway ROW Permits · HOA Approval
Timeline: When to Plan Linear Drains
| Phase | Do this | Avoid this |
|---|---|---|
| Design | Define flow arrows, low points, drain locations, and discharge path | “We’ll add drains if needed” after hardscape is set |
| Subgrade | Install drain bodies and outlet piping before final finishes | Cutting finished porcelain or pavers later |
| QA | Photo proof before cover-up and water test where appropriate | Burying drain routing with no documentation |
Maintenance
- Clean routinely: remove leaves and sediment before it clogs outlets.
- Flush occasionally: flush lines and confirm flow to outlet.
- Keep access: do not bury cleanouts and access points behind planters or furniture.
Quote Checklist: What to Demand in Writing
This checklist filters out incomplete bids. If it is not written, it is not included.
- Drain type and product: slot drain vs trench drain, model line, load rating if driveway.
- Locations: plan view with flow arrows and low points.
- Concrete collar detail: support requirements, not just “set in concrete.”
- Outlet size and routing: pipe size, slope intent, cleanouts, and discharge destination.
- Discharge plan: where water goes in heavy storms, stated in writing.
- QA photos before cover-up: drain body placement, outlet routing, and cleanouts documented.
FAQs
What is the difference between a slot drain and a trench drain?
A slot drain is a minimalist linear drain with a narrow opening, often used at doors and pool decks for a clean modern look. A trench drain typically uses a wider channel with a grate, often used for higher flow areas like driveways and intercept lines.
Do I need a linear drain if my patio is sloped?
Not always. Slope is the first line of defense. Linear drains are most valuable as insurance at thresholds, doors, and hardscape edges where water intrusion or staining risk is high.
Why do trench drains settle and rattle?
Usually because the drain body was not supported with a proper concrete collar, the base was not compacted correctly, or the outlet piping created voids. Elite installs specify support details and document them before cover-up.
Do driveway trench drains require permits?
Sometimes, especially if the scope touches public frontage or right-of-way conditions. The best approach is to screen ROW exposure and discharge path early.
Service Area
We design-build drainage-first hardscapes across San Diego County including Rancho Santa Fe (92067/92091), La Jolla (92037), Del Mar (92014), Solana Beach (92075), Coronado (92118), Cardiff-by-the-Sea (92007), Encinitas (92024), Carmel Valley (92130), and Santaluz/Del Sur (92127).