# Side-yard and swale drainage in Allen, TX, from a drainage contractor who knows what may sit in a swale > Drainage contractor in Allen, TX: side-yard swales, basins and French drains planned around Allen's swale encroachment detail and its ROW permits. Book a visit. URL: https://clayplanodrainagecompany.com/service-areas/allen/ Drainage contractor in Allen, TX: side-yard swales, basins and French drains planned around Allen's swale encroachment detail and its ROW permits. Book a visit. Last Updated: November 11, 2026 - **Permits:** City of Allen Engineering (right-of-way permits) - **Storm drainage:** City of Allen (streets, right-of-way and drainage easements) - **The rule that changes the job:** Slab max 1 ft into swale ## What usually starts a drainage job in Allen ### A slab poured across the swale A patio or AC pad reaches into the strip between houses and water backs up behind it. Allen's detail lets a slab reach no more than 1 foot into the side swale. ### A fence that blocks the flow A screening fence sits on the swale line and dams it. Allen's detail has the fence cantilevered over the drainage easement, so posts stay out of the water's path. ### A flat lot near Rowlett Creek In west Allen the soil maps show Tinn clay on 0 to 1 percent ground that floods now and then. Water has almost no fall to work with there. ### A line out to the curb The route ends in the parkway. Allen issues right-of-way permits online, and locates for that work need the permit number, a Texas811 ticket and a location map. ## Side yard holding water after every storm? The strip between two houses has to carry water from both back yards to the street, and anything built in it slows the flow. [Clay Plano Drainage Company](https://clayplanodrainagecompany.com/) fixes side-yard swales and builds French drains, basins and channel drains in Allen. Allen spells out what may sit in a side swale. That detail is our starting point for deciding whether to reshape the swale, move water past an obstruction, or both. ## What Allen allows in a side swale Allen’s standard construction details for residential lot drainage, sheets SD-RL01 to SD-RL04, show how a lot sheds water and how close improvements may come to the swale. The current set dates from a May 2017 revision. The details group lots into three grading types, A, B and C, by how the water leaves. They also cover side-swale encroachment, the part that matters most in a side yard: | What sits in the side yard | What Allen’s detail allows | What it means for drainage | | --- | --- | --- | | A concrete slab (patio, walk, AC pad) | No more than 1 foot into the side swale | A wider slab pinches the channel and backs water up | | A screening fence | Cantilevered over the drainage easement | Posts stay out of the water’s path | | The fence’s reach | Not past the slab footprint | The swale stays open beyond the slab | When a slab or fence already crowds the swale, there are two ways forward. One is to bring it back within the detail. The other is to let the water pass underneath with a basin upstream and solid pipe past the pinch point. We lay out both on the estimate. ## Fixing a crowded side yard The fix depends on how much room is left. A swale that only lost its fall gets reshaped. A swale with a slab across it needs a way past. - **Reshape the swale.** Where the strip is open, we re-cut the channel to a steady fall from the back corner to the street. - **Pipe past the pinch.** A [catch basin](https://clayplanodrainagecompany.com/catch-basins/) collects water above the slab or pad, and solid pipe carries it under to open ground. - **A channel drain across a walk.** Where a side walk runs the full length, a [channel drain](https://clayplanodrainagecompany.com/channel-drains/) can catch sheet flow and hand it to a buried line. - **Both neighbors in mind.** The swale serves two lots, so the work keeps it draining for the house next door too. The [side-yard drainage page](https://clayplanodrainagecompany.com/side-yard-drainage/) covers the method, and the [guide to drainage easements](https://clayplanodrainagecompany.com/guide/drainage-easements-plano/) explains how to find the easement on your plat. ## Flat ground near Rowlett Creek Soil maps put Tinn clay along the Bethany and Rowlett Creek areas of west Allen. It sits on 0 to 1 percent slopes, it is listed as occasionally flooded, and it drains very slowly. That combination is hard on a gravity drain. With almost no fall across the lot, a pipe has nowhere to drop to, and the soil around it won’t take the water either. On a flat west-side lot, the realistic options are: - **Regrade toward the street,** if the front of the lot sits low enough to receive it. - **A [yard pump basin](https://clayplanodrainagecompany.com/sump-pump-drainage/)** that collects water at the low point and lifts it to a street-side outlet. - **Check the floodplain first.** Ground that floods from the creek is a different problem from a yard that won’t drain, and work there is confirmed with the city for the address. The [floodplain or drainage problem guide](https://clayplanodrainagecompany.com/guide/floodplain-or-drainage-problem/) helps sort one from the other. ## Central Allen’s heavy clay Most of central Allen sits on Houston Black clay, the same heavy clay found under much of Plano. It takes in water very slowly and swells when wet, so rain sits on top of the lawn instead of soaking in. A [French drain](https://clayplanodrainagecompany.com/french-drain-installation/) in that soil is built for it: - **More stone around the pipe,** so the trench holds water while the pipe carries it away. - **Filter fabric against the clay,** to keep fines from silting the stone. - **An outlet that works every time,** because the soil around the trench won’t take the water. The guide to [French drains in clay soil](https://clayplanodrainagecompany.com/guide/french-drains-in-clay-soil/) shows the build. If a patch of lawn stays wet even in dry weather, the cause may be a sprinkler leak or seepage instead; the [soggy yard guide](https://clayplanodrainagecompany.com/guide/soggy-yard-no-rain/) explains how to tell. ## Planning a patio or fence in the side yard? The easiest swale to fix is the one that never gets blocked. If you’re about to pour a slab, set an AC pad or put up a fence beside the house, a few checks first can save a drainage job later: - **Find the easement** on your plat before you mark the fence line. - **Keep slabs within a foot** of the swale edge, as Allen’s detail allows. - **Ask how the fence spans the swale,** so the posts land outside the channel. - **Leave the low line open** from the back corner to the street, with no edging or beds across it. - **Think about downspouts** on that side, which may need a buried line before the slab goes down. If the slab has to go where water runs today, a solid pipe under it, laid before the pour, is far simpler than cutting concrete later. We can plan that line with you ahead of the work. ## Work in the right-of-way When the outlet crosses the parkway, Allen’s right-of-way process applies. The city has taken applications online since March 3, 2026, and asks applicants to check its GIS utility map before they apply. Locates for right-of-way work need three things: the permit number, a Texas811 ticket and a location map of the work. We handle that sequence as part of the job and show the permit as its own line on the written estimate. ## Allen and the cities around it Allen spans US 75 and SH 121, with SH 5 along its east side. Cross a city line and the drainage rules change: - **[McKinney](https://clayplanodrainagecompany.com/service-areas/mckinney/)** leaves private swales and natural creeks on a lot to the owner to maintain, even inside an easement. - **[Lucas](https://clayplanodrainagecompany.com/service-areas/lucas/)** asks for a permit before work in or near a street, right-of-way, easement or public way. - **[Frisco](https://clayplanodrainagecompany.com/service-areas/frisco/)** requires a Public Works permit for any work in city right-of-way or easements. ## How we approach an Allen side yard The swale comes first, the pipe second. A side-yard fix is usually about giving the water back its path. - **Measure the encroachment.** How far each slab, pad and fence reaches into the swale. - **Read the fall** from the back corner to the street, not just where it is wet. - **Choose the outlet** before the route, at the street side of the lot. - **Run water through** the swale or pipe before backfill. - **Restore and walk through.** Sod back in strips, sprinkler lines repaired, and the route shown to you. Where the whole lot tilts the wrong way, [yard regrading](https://clayplanodrainagecompany.com/yard-grading/) resets the slope before any pipe goes in. ## Drainage services in Allen - [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/) - [Service**Channel drains** A grated trench set into concrete at a driveway, patio or garage apron that catches water running across the paving before it reaches the house.](https://clayplanodrainagecompany.com/channel-drains/) - [Service**Catch basins** A grated box set at the lowest point of a lawn, bed edge or patio that takes in surface water and sends it through solid pipe to an outlet.](https://clayplanodrainagecompany.com/catch-basins/) - [Service**Yard sump pumps** An outdoor pump basin that collects yard water on a lot with no downhill path and pushes it through a buried line to the street or another approved outlet.](https://clayplanodrainagecompany.com/sump-pump-drainage/) - [Service**French drains** A trench of washed stone and pipe that collects water held in the soil and carries it to a legal outlet at the street side of the lot.](https://clayplanodrainagecompany.com/french-drain-installation/) - [Service**Yard grading** Reshaping the soil so the ground falls away from the slab and toward a swale or the street, set to measured slopes instead of guesswork.](https://clayplanodrainagecompany.com/yard-grading/) ## How a job usually runs in Allen ### Photos of the side yard Send the address and pictures of the strip between the houses, from the back corner to the street. Note any slab, AC pad or fence that sits in the swale. ### Fall and footprint On the visit we read the fall along the swale, measure how far each slab reaches into it and probe the soil. The written estimate shows what changes and where the water leaves. ### Permit and locates For parkway work we check Allen's GIS utility map first, apply for the right-of-way permit online and send the permit number, the Texas811 ticket and a location map for locates. ### Shape, pipe, test We cut the sod in strips, reshape the swale or lay solid pipe past the pinch point, run water down it before backfill and put the sod and sprinkler lines back. ## Neighborhoods, landmarks and routes - Central Allen - West Allen ### Landmarks - Rowlett Creek ### Routes - US 75 - SH 121 (Sam Rayburn Tollway) - SH 5 (Greenville Avenue) ## Allen: questions ### How far can my patio extend into the side swale in Allen? Allen's residential lot drainage detail allows a concrete slab no more than 1 foot into the side swale. A slab that reaches further narrows the channel, and water backs up behind it. Where that has happened, a basin and solid pipe can carry the water past. ### Can I put a fence in the drainage easement beside my Allen house? Allen's detail shows a screening fence cantilevered over the drainage easement, not extending past the slab footprint, so the posts stay out of the swale. If a fence already blocks the flow, we plan the drain around it and point out where the detail differs. ### What does side-yard drainage cost in Allen? We charge the same rates in Allen as anywhere else we work. Our typical range for a side-yard swale or pipe is $1,500 to $4,000 per side yard, a channel drain runs $60 to $150 per foot, and a yard pump basin with discharge is $1,500 to $4,000. The site visit and written estimate set yours. ### What does Allen need before work in the right-of-way? A right-of-way permit through the city's online application, which Allen has used since March 3, 2026. The city asks applicants to review its GIS utility map first, and locate requests need the permit number, a Texas811 ticket and a location map. ### Why won't my west Allen yard drain no matter what I do? Parts of west Allen near Rowlett Creek sit on Tinn clay, mapped on 0 to 1 percent slopes and occasionally flooded. With almost no fall and very slow soil, gravity drains have little to work with, so a pump basin or regrading toward the street is often the practical fix. ## Nearby service areas - [City of McKinney Engineering (Engineering Design Manual)**McKinney**](https://clayplanodrainagecompany.com/service-areas/mckinney/) - [City of Lucas (permits for work in or near streets, right-of-way and easements)**Lucas**](https://clayplanodrainagecompany.com/service-areas/lucas/) - [City of Frisco Public Works (right-of-way and easement permits)**Frisco**](https://clayplanodrainagecompany.com/service-areas/frisco/) ## Guides for yards in Allen - [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/) - [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/) - [Learn**Do French drains work in clay soil?** Plano's clay moves water at a crawl, which changes where a trench goes, how much stone it holds and what keeps it from silting up. What works here, and why some clay drains quit.](https://clayplanodrainagecompany.com/guide/french-drains-in-clay-soil/) - [Learn**Why is my yard wet when it hasn't rained?** A soggy patch in a dry week has a water source you can often find in an afternoon. The order to check things in, the meter test for hidden leaks, and when it really is a drainage problem.](https://clayplanodrainagecompany.com/guide/soggy-yard-no-rain/) ## Get an estimate in Allen Tell us what the water is doing and where the house is in Allen.