Storm Drainage Prep for Flat Lots & Slopes Just because your property sits on a relatively flat area doesn’t mean it’s immune to flood damage. In fact, flat lots can be harder to drain effectively because there isn’t enough natural “fall” (slope) for water to move downhill into drains or disperse safely on its own.
Walk your property before storm season. Identify where water collects, where it should go, and what could clog or fail during a high-volume downpour.
Quick checklist (start here)
- Inspect trees for health, imbalance, and weak limbs.
- Remove/repair rodent burrows—especially above slopes.
- Clean drains, gutters, catch basins, and sumps; confirm daylighting points.
- Confirm water flows away from buildings; keep stucco weep screeds exposed.
- Turn irrigation off when storms are forecasted; know your main shutoff.
- Stabilize slopes where possible; stage erosion-control materials.
- Keep emergency supplies in a dry, accessible location.
Check your trees
With drought stress taking a toll on trees, storm season is a smart time to do a basic health check and risk assessment. Drought-stressed trees can be weaker, and sudden high-volume moisture plus wind can overload branches that are already compromised.
Heavy, unhealthy, or unbalanced trees are more likely to fail when soil becomes saturated. Falling trees can break sprinkler lines, damage drains, and redirect water flow—sometimes turning a manageable issue into a much larger one.
Hillside rodents, ground squirrels, rabbits, and other burrowing animals
Eliminate burrowing animals and collapse/fill their burrows. Stormwater can funnel into holes and create an “underground dam” effect—water builds pressure and can burst out, causing major erosion or slope failure.
Pay special attention to rodent holes in lawns or flat areas above slopes—these zones can collect and concentrate large amounts of water. Foraging animals can also worsen slope issues by stripping vegetation that protects soil.
V-ditches on slopes (concrete drainage swales)
Keep V-ditches clean and make sure the “daylighting” outlet remains open. Remove loose soil that could wash into the ditch and clog it. Also check for eroded areas where the soil has dropped below the edge of the V-ditch.
If water can’t roll smoothly into the swale, it may pool or cut beneath it. Undercutting can crack, break, or wash out the ditch entirely—often creating a domino effect if the water no longer reaches its intended discharge point.
Check & clean drains, rain gutters, and sumps
Check where drains “daylight” (where the pipe discharges). Also pay attention to your neighbors’ drainage—water doesn’t respect property lines, and their runoff can impact your lot.
Leaf guards can help keep gutters from clogging, but be mindful of where debris goes. In some situations, gutters that collect heavy debris are better not tied directly into underground drains. Instead, allow them to discharge near a drain inlet so leaves and grit don’t clog the drain line.
If you have sump pumps, clear debris and test operation. In critical locations, consider a secondary backup pump set at a higher elevation. Know where the pumped water goes—and plan for power outages (a failed pump during a storm can flood quickly).
Check water flow & don’t bury the “weep screed” on buildings
Make sure water flows away from walls and toward the drainage system. On stucco buildings, do not bury the weep screed near the bottom of the wall. This is the drainage point for moisture that enters the stucco assembly—if it’s blocked, water can build up and migrate through the wall.
Many older buildings don’t have a weep screed, but the same principle applies: don’t bury soil or mulch above the footing line.
Turn irrigation timers off & know where your main shutoff is
Don’t make a storm situation worse—turn irrigation timers off once storms are forecasted. Many Garden View accounts have rain sensors that shut controllers down automatically, but sensors still need to be functional and enabled before storm season.
Also, know where your main water shutoff is (especially the irrigation main). An emergency is not the time to go hunting for valves.
Protecting slopes
Historically, deep-rooted planting has been the best long-term approach to minimizing slope slippage. However, drought has weakened or eliminated many slope plantings, reducing natural stabilization.
Mulch can help in many situations. During heavy rain, mulch can slow surface flow and absorb water. As it becomes saturated, it can also “seal” and shed water—reducing erosion in some cases.
Other products that can slow or redirect water include sandbags, straw wattles, jute netting, plastic sheeting, gabions, silt fencing, mulch blankets, and hydroseed-applied polymers.
Have emergency materials on hand
We recommend storing an emergency package in a dry, accessible location. A typical kit may include:
- Plastic sheeting
- At least 50 sandbags
- Rope/tie-downs (to secure plastic and sandbags)
- Stakes and a sledgehammer
- Shovel
- Water diversion tubes
- Extra sump pump + extension cords
Every property is different. Look for cause-and-effect scenarios, use common sense, and weigh how much you want to invest to reduce exposure to future losses. Let’s hope we get enough rain to ease the drought—without causing devastating damage.