# What does Plano's drainage design manual mean for homeowners?

> Plano's drainage design manual for homeowners: lots drain to the street, no lot-to-lot drainage, side swale depth and fall, curb permits and HOA review.

URL: https://clayplanodrainagecompany.com/guide/plano-drainage-rules/

The city's Stormwater Design Manual is written for engineers, but a handful of its rules decide what you can do in your own yard. Here they are in plain words, with the numbers.

Last Updated: November 11, 2026

The short answer

For a house lot, Plano's Stormwater Design Manual comes down to four rules: lots drain to the street, lot-to-lot drainage is not permitted, natural flow can't be diverted or held back to harm a neighbor, and side swales need depth and at least a 1% fall. Work in the public right-of-way needs a city permit.

Key takeaways

- Plano designs house lots to drain to the street; lot-to-lot drainage is not permitted.
- Side swales are drawn at least 0.25 feet (3 inches) deep across 3 feet each side of the line.
- Side and back yards need at least a 1% fall, which is 1 foot for every 100 feet.
- Curb outlets and other right-of-way work go through the city's Engineering Permit for public infrastructure.
- HOA approval, where your subdivision requires it, is separate from any city permit.

## Planning drainage work and wondering what the city allows?

Plano’s Stormwater Design Manual, the current edition dating from 2024, sets the rules for how land in the city drains. Most of it covers streets, channels and new subdivisions, but a few rules decide what you can do in your own yard.

[Clay Plano Drainage Company](https://clayplanodrainagecompany.com/) plans yard and [side-yard drainage](https://clayplanodrainagecompany.com/side-yard-drainage/) around those rules on every Plano job. This guide pulls out the parts that matter to a homeowner and explains each with its numbers.

## Rule 1: House lots drain to the street

The manual’s site grading section says residential lots generally drain to the street. It sorts house lots into grading types, labeled A, B and C, by how water crosses them on the way out.

In practice, that sets the outlet for almost every yard drain in Plano:

- **The front lawn,** through a pop-up emitter that lets water out onto open grass toward the curb.
- **An existing line** that already reaches the street, once we prove it still flows.
- **The curb itself,** with the city permit described below.

The guide to [where yard drain water can go](https://clayplanodrainagecompany.com/guide/where-can-yard-drain-water-go/) compares those outlets side by side.

## Rule 2: No lot-to-lot drainage

Lot-to-lot drainage is not permitted. Water from your lot shouldn’t be sent across a neighbor’s lot to get to the street, and theirs shouldn’t cross yours.

The manual’s lot drainage figure allows an exception only where an engineer has approved it. The same section says natural flow must not be diverted or impounded in a way that damages adjacent or downstream property, the city version of a rule [Texas law](https://clayplanodrainagecompany.com/guide/neighbor-water-runoff-texas/) applies statewide.

### What it means for your project

The rule shapes ordinary projects, not just new subdivisions:

- A downspout line can’t end at the shared fence.
- A new patio’s runoff needs its own route to the street.
- A berm or raised bed that dams water on the line works against the rule.

## Rule 3: Side swales need depth and fall

Figure 1 of the manual draws the side swale between houses. It shows a swale at least 0.25 feet deep, about 3 inches, spread across 3 feet on each side of the property line, so about 6 feet wide in all.

The same figure asks for at least a 1% slope along side and back yards. Here is what that fall means on real lots:

| Length of the run | Least fall at 1% |
| --- | --- |
| 40-foot side yard | About 5 inches |
| 60-foot side yard | About 7 inches |
| 100-foot back yard run | 12 inches |

Most Plano soils are mapped on 0 to 3% slopes, so there isn’t much natural fall to spare. A few inches of fill, a slab edge or a bed can flatten a side swale below that 1%. [Yard regrading](https://clayplanodrainagecompany.com/yard-grading/) restores it.

## Rule 4: Owners maintain their lot drainage

The lot drainage figure marks house drainage easements as privately maintained. The city’s drainage maintenance guidance adds two more points:

- **Keep it clear.** Residents should keep drainage ditches on their property free of debris and vegetation.
- **Don’t dump in it.** Dumping debris into ditches or channels is illegal, and Plano Public Works takes reports.

Easements on your plat also limit what you can build, from fences to sheds. That’s a topic of its own in the guide to [drainage easements in Plano](https://clayplanodrainagecompany.com/guide/drainage-easements-plano/).

## Rule 5: Right-of-way work needs a permit

The parkway between the sidewalk and the street, and the curb itself, are public right-of-way. Any drainage work there goes through Plano’s Engineering Permit for public infrastructure.

- **Permit types** include excavation and grading, storm drain, and paving or drive approaches.
- **Registration.** Firms working in the right-of-way register with the city each year and show proof of insurance under the right-of-way ordinance, Section 19-68.
- **On site.** The approved permit stays at the worksite while the work happens.
- **Where it goes.** Applications go to the city’s engineering permits office at [EngPermits@plano.gov](mailto:EngPermits@plano.gov).

We arrange that permit as part of the job when a route reaches the curb. The details of a curb connection are confirmed for each address with the city before the route is final.

## Before and during the dig

Two more city requirements touch every drainage job, even one that never leaves the lot.

1. **Locates first.** Plano’s outdoor improvements guidance tells residents to call before they dig, through Texas811.
2. **Keep soil out of the storm system.** Plano runs its storm sewers under a state permit with controls for construction runoff, so silt controls protect street inlets while trenches are open.

The guide to [what happens during drainage installation](https://clayplanodrainagecompany.com/guide/what-happens-during-drainage-installation/) shows how both fit into the work.

## HOA approval is a separate step

A city permit and HOA approval answer different questions. The city cares about the right-of-way and how water leaves; an HOA may care about what the work looks like and where it sits.

Some subdivisions require HOA approval for exterior work, and their guidelines say so. Check yours before work starts. Our written estimate gives you the route, the outlet and the restoration to describe in the request.

## Plano compared with nearby cities

The rules around Plano point the same way, with different numbers. If you’re just over the line, these are worth knowing.

| City | A detail its rules add |
| --- | --- |
| [McKinney](https://clayplanodrainagecompany.com/service-areas/mckinney/) | Grade falls at least 6 inches in the first 10 feet from a building; earthen swales 2% minimum |
| [Garland](https://clayplanodrainagecompany.com/service-areas/garland/) | House pad at least 12 inches above the lowest primary drainage point; unpaved swales 1% minimum |
| [Allen](https://clayplanodrainagecompany.com/service-areas/allen/) | A slab may reach no more than 1 foot into the side swale |
| [Prosper](https://clayplanodrainagecompany.com/service-areas/prosper/) | One curb core per lot, no more than 3 inches across, with a right-of-way permit |

If you’re planning work and want the rules applied to your lot, call [(469) 551-8518](tel:+14695518518) or send photos through the form below. We’ll measure the fall, find the outlet and show you how the plan fits the manual.

## Questions about this guide

### Does Plano require a permit for a backyard French drain?

Work in the public right-of-way does, which is where a curb outlet sits. For a drain that stays entirely inside your lot and leaves through an emitter in your own lawn, we confirm what applies to your address before work starts. HOA approval is a separate question for your subdivision.

### What are Type A, B and C lots in Plano?

They're the lot grading types in Plano's Stormwater Design Manual, sorted by how water travels across a house lot to leave it. The types differ in the path, through the front yard, side swales or both, but the manual generally sends house lots to the street rather than onto the lot next door.

### Can I change the grade of my yard in Plano?

Within your lot, yes, as long as water still leaves toward the street and doesn't end up on your neighbor's lot. Keep the side swales at their depth and fall, keep fill out of any easement on the plat, and get the city's permit if the work reaches the right-of-way.

## Related service

- [Service**Side yard drainage** Restoring or replacing the shallow swale between two houses so water from the back yard reaches the street instead of pooling along the fence and the slab.](https://clayplanodrainagecompany.com/side-yard-drainage/)

## More guides

- [Learn**Drainage easement rules in Plano: what can you build in one?** The strip along your side or back line may be yours on paper and reserved for water in practice. How to find it, what tends to block it, and how to plan around it.](https://clayplanodrainagecompany.com/guide/drainage-easements-plano/)
- [Decision Guide**Where do you drain a French drain in Plano?** The outlet decides the design, so we choose it first. Every option a Plano yard has, what each one needs, and how to pick when the lot is flat.](https://clayplanodrainagecompany.com/guide/where-can-yard-drain-water-go/)
- [Learn**What does Texas law say about a neighbor's water runoff?** Natural runoff from a higher lot and water a neighbor has redirected are two different problems. How to tell them apart, write it down, and protect your yard without pushing water back.](https://clayplanodrainagecompany.com/guide/neighbor-water-runoff-texas/)
- [Learn**What happens during a drainage installation?** From the first look at the yard to the last walk along the route. What we do at each stage, what we ask of you, and what the lawn looks like when we leave.](https://clayplanodrainagecompany.com/guide/what-happens-during-drainage-installation/)
- [Learn**Is it a floodplain problem or a yard drainage problem?** A flooded back yard by a creek and a flooded back yard on a flat lot look alike from the patio. Where the water came from decides who can fix it, and what a yard drain can and can't do.](https://clayplanodrainagecompany.com/guide/floodplain-or-drainage-problem/)

## Get an estimate for your yard

Tell us where the water stands and when. We walk the yard and send a written estimate.