Series: Storm Season / El Niño Prep (Part 4)
What drainage upgrades work best for a commercial landscape? Match the fix to the problem, and start with the simplest option that solves it. Fix the grade, fill the low spots, and keep irrigation off before storms. Then add planted features such as bioswales that slow and soak up water. Finally, use piped systems, such as French drains and catch basins, or engineered basins when water has to be collected and moved. In many cases, the sustainable options come first because they work with the landscape instead of just sending water somewhere else.
This is Part 4 of our storm-prep series. In Drainage 101 we showed you how to find problems. Here, we cover what to actually install, building on A Super El Niño Is Coming and the tree-risk guidance in Part 3.
Save this guide before your next site walk, and share it with anyone who manages a property with standing water.
Start With the Simple Fixes
Before anyone digs a trench, three low-cost fixes deserve a look. Each one changes where water goes without adding hardware.
1. Use Smart Controllers to Turn Irrigation Off Before Storms
Irrigation that runs on saturated ground adds runoff to a site that is already struggling. EPA WaterSense labels two types of controllers that help. Weather-based controllers adjust schedules to local weather and landscape conditions, and soil moisture-based controllers prevent watering when the soil is already moist. A basic rain sensor can also interrupt irrigation after a set amount of rainfall, although it does not replace correct scheduling.
For that reason, check your controllers before the first storm. Confirm that rain delay or weather features are active, that sensors are working, and that nobody has left a manual schedule running through the wet season. Meanwhile, if you manage several sites, remember that each controller needs its own check.
2. Eliminate Low Spots Before the Rain Does
A low spot is simply a place where water has nowhere else to go. Filling it with soil, then planting groundcover, removes that pocket and gives roots and foliage a way to slow water down. As a result, water moves across the surface instead of pooling.
Do this carefully: Keep new soil below siding, weep screeds, and any trunk flare. Do not bury the base of a tree or shrub. Most importantly, confirm where the water will go once the low spot is gone, because filling one hollow can push water toward a building or a neighboring property.
3. Make Sure the Landscape Slopes Away From Buildings
Water should leave a building, not sit against it. A widely used benchmark in the International Residential Code calls for the ground to fall at least 6 inches within the first 10 feet from a foundation, which is a 5% slope. It also calls for hard surfaces within 10 feet to slope at least 2% away. Where a wall, slope, or property line makes that impossible, the code calls for a drain or swale instead.
Commercial buildings follow the California Building Code and the project’s own civil drawings, so treat that benchmark as a starting point and compare it with your plans. In practice, a long, level or backward-sloping strip beside a foundation is one of the most common problems we see.
Sustainable Upgrades That Handle More Water
Bioswales
A bioswale is a shallow channel, densely planted with grasses, shrubs, or other vegetation, designed to slow, filter, and soak in storm water. It works well along parking lots, drive aisles, and building edges where runoff is moderate. Contra Costa County lists bioswales among its green infrastructure practices, and larger projects may fall under local stormwater requirements.
Design basics that matter:
- Size: a common guideline sets the swale surface at about 1% of the area that drains to it.
- Slope: slopes of 5% or less are recommended, and 1% to 4% is ideal.
- Check dams: at slopes near or above 4%, check dams slow the flow. They should not be built from earth, which erodes, and are often spaced about every 50 feet.
- Plants: dense, deep-rooted native grasses and plants hold soil and take up water.
- Overflow: every bioswale needs a safe overflow path that does not send water toward buildings, unstable slopes, or neighbors.
- Setbacks: place rain gardens and bioswales at least 10 feet from a foundation.
Bay Area note: Many East Bay soils contain a lot of clay, and clay absorbs water slowly. In that case, a bioswale may need an underdrain, a shallower depth, or compost to improve how quickly water soaks in. Because of that, a site-specific assessment matters more than a standard template.
Piped Systems for When Water Has to Be Moved
French Drains
A French drain is a trench filled with gravel and a perforated pipe. It collects water over a wide area, including groundwater and surface runoff, and carries it downhill. It suits wet strips, seepage near a foundation, and runoff from a slope. However, it needs a place to discharge, and it must be kept free of silt.
Catch Basins
A catch basin is a box set into the ground with a grate on top. Surface water enters through the grate and is directed into a drain pipe. It works best at a clear low point where water already collects. As we covered in Drainage 101, leaves, mulch, and sediment can clog a basin, so it needs cleaning before storm season.
Dry Wells
When there is no downhill outlet, a dry well gives collected water a place to soak in underground. Whether it will work depends on the soil and the site, so an engineer should confirm it first.
In many cases, the best answer combines these tools. For example, a catch basin under a downspout can feed a pipe that leads to a French drain, a bioswale, or a basin.
Retention and Detention Basins
Basins store larger volumes of water. The two terms are often confused:
- Detention basin: often called a dry pond. It holds water temporarily after a storm and releases it slowly at a controlled rate.
- Retention basin: it holds water permanently, such as a pond, and is often used to improve water quality or add visual value.
On commercial properties, basins are usually engineered by a civil engineer and may be required as part of a stormwater permit. Once built, they need regular inspection of outlets, removal of sediment and debris, and care for the plantings around them.
Which Upgrade Fits Which Problem?
If you see… | Start with | Add if needed |
Puddles in a lawn or bed | Fill the low spot, add soil and groundcover | Catch basin or French drain |
Water against a building | Regrade away from the foundation, check downspouts | French drain or swale |
Runoff from a parking lot or hard surface | Bioswale or planted strip | Catch basin and overflow route |
Wet strip or seepage on a slope | French drain with a clear outlet | Engineer review for slope stability |
Overwatered, soggy turf | Smart controller with rain delay or soil moisture sensor | Irrigation audit |
Large site with a lot of runoff | Basin designed by a civil engineer | Bioswales upstream to slow flow |
Not sure which row you are in? Request a pre-storm drainage walkthrough and we will help you match the fix to the problem. Contact Rubicon Landscape Group.
Mistakes That Make Drainage Worse
- Filling a low spot with nowhere for water to go. The water will simply find another low place.
- Installing a French drain with no outlet. A drain that cannot discharge only moves the pool.
- Sending water toward a neighbor or a slope. Overflow should never move water toward buildings, unstable slopes, or adjoining property.
- Leaving irrigation running through storms. It wastes water and adds to saturation.
- Skipping maintenance. Basins, swales, and drains lose capacity as sediment builds up.
- Skipping permits and engineering. Larger changes may trigger city or stormwater requirements.
Quick Answers
What is the difference between a French drain and a catch basin?
A French drain is a long, gravel-filled trench with a perforated pipe that collects water over an area. A catch basin is a box with a grate that collects water at one low point and directs it into a pipe.
How do I stop water pooling on my commercial property?
Find out why it pools: a low spot, poor grading, a clogged basin, or irrigation. Fix the cause first, then add drainage hardware if water still collects.
Do smart irrigation controllers help with storm prep?
Yes. Weather-based and soil moisture-based controllers delay or skip watering when it is not needed, which reduces runoff and saturation. They work best when they are programmed and maintained correctly.
What is the difference between a retention basin and a detention basin?
A detention basin holds water temporarily and releases it slowly. A retention basin holds water permanently.
Plan It in Phases
Drainage work does not have to happen all at once. Costs vary with soils, access, permits, and the size of the site. In general, the simplest fixes come first, and larger upgrades can follow in phases across budget cycles. Because every property is different, we start with a walkthrough and a written plan instead of a one-size-fits-all package.
Rubicon offers free estimates, free consultations, and free phased planning for rehabilitation and enhancement projects, so you can see the full picture before you commit.
What Comes Next in the Series
Next, we close out the pre-storm checklist: a final round of checks to run right before the wettest weeks arrive. Follow Rubicon so you do not miss it.
Ready to Upgrade Before the Rain Arrives?
Schedule a pre-storm drainage walkthrough with Rubicon. We will review grading, low spots, irrigation, basins, and slopes together, recommend the simplest effective upgrades, and give you a phased plan.
Resources for Going Deeper
- Save Our Water: California’s statewide water conservation program, including outdoor watering guidance
- QWEL (Qualified Water Efficient Landscaper): EPA WaterSense-recognized certification covering irrigation auditing and system design
- NALP (National Association of Landscape Professionals): industry certification and continuing education for landscape and irrigation professionals
- CLCA (California Landscape Contractors Association): California-specific water management certification and continuing education
Why Rubicon
For more than 30 years, Rubicon Landscape has provided dependable, professional landscape services throughout the Bay Area, helping property owners and managers maintain landscapes that are healthy, attractive, and reliably well-functioning.
Our approach is built on quality workmanship, responsive service, and proactive problem-solving, the kind of long-term partnership that protects your landscape investment and delivers consistent results, year after year.
As a division of Rubicon Programs, that work also creates real community impact. Every project supports employment opportunities and workforce development that strengthen the communities we serve.
Professional landscape services. Reliable results. Meaningful community impact.
Looking for a Landscape Partner?
From commercial properties and municipal facilities to institutional sites and multi-site portfolios, our services include:
- Commercial Landscape Maintenance & Installation
- Landscape Construction & Renovation
- Irrigation Installation, Repair & Management
- Water Efficiency & Conservation Solutions
- Regenerative Services: Horticulture, Turf Care & Weed Management
