Updated October 2026
The first big storm of the winter is the most expensive one. Not because it's the strongest, but because it hits properties that spent all summer drying out and nobody has looked at the drains since March. For property managers and HOA boards in San Luis Obispo County, the fix is a walk-through in October, when it's dry, the ground is easy to read, and a contractor can still get to you in a week instead of a month.
This is the checklist our team uses on commercial sites, HOA common areas, and multi-family properties from Paso Robles to Santa Maria. Most of it takes an hour with a clipboard and a phone camera. If you'd rather have a second set of eyes, our San Luis Obispo team is doing a limited number of free property walks this fall. You can request a free property walk here.
A note on this winter
NOAA's Climate Prediction Center has an El Niño Advisory in effect, and its seasonal outlook leans toward a wetter than normal winter on the California coast. A forecast is not a guarantee. The last two strong El Niño winters on the Central Coast looked very different from each other. What the forecast does tell you is that the odds have shifted, and the cost of checking now is a lot lower than the cost of finding out in January.
1. Trees and large shrubs
Wind arrives before the rain and takes the weak limbs first. Walk every tree that overhangs a roof, a parking area, a walkway, or a neighbor's property.
- Look for dead or cracked limbs, especially in eucalyptus, pine, and older oaks.
- Check for trees leaning more than they did last year. Soil heaving on the uphill side of a trunk is a warning sign.
- Thin dense canopies on young trees so wind passes through instead of pushing them over.
- Confirm your tree care vendor has done a fall inspection in writing. If a limb comes down on a car, the paper trail matters.
2. Gutters, downspouts, and roof drains
Most foundation and slab problems start at a downspout. Clearing gutters is the easy half. The other half is where the water goes when it leaves.
- Every downspout should discharge into a drain line, a splash block, or at least four feet from the building.
- Look for dirt lines, staining, or a small crater in the soil at the base of a downspout. That's water hitting the foundation.
- On flat commercial roofs, confirm the scuppers and overflow drains are clear. A clogged roof drain holds thousands of pounds of water.
3. Site drainage and grading
This is the part most property walks skip, and it's where the big repairs come from. The good news is that water leaves a record you can read in dry weather.
- Lift a catch basin grate. More than an inch of sediment means the line needs clearing, and standing water two days after the last rain means it may need a camera run for roots.
- Walk the building perimeter. Soil should slope away from the foundation. Mulch that has built up above the slab line pushes water the wrong way.
- Check bioswales and detention areas. Inlets and outlets should be clear, with no sediment bar at the inflow. If water sat in a swale for five days after last winter's storms, it isn't draining, and on most commercial sites that maintenance is the owner's obligation under the stormwater permit.
- Look at the low points of the parking lot. Silt lines on the asphalt show you where water pooled last year.
If you want to see what these three problems look like on a real property, you can watch Tony walk a property in about a minute. For properties that need more than clearing, this is the category where drainage and grading work gets planned.
4. Slopes and retaining walls
The Central Coast is full of hillside properties and cut slopes behind buildings. A wall that held fine last winter can fail the next one if the drainage behind it has clogged.
- Look for new cracks, bulging, or a lean that wasn't there in spring.
- Check that weep holes and drain outlets at the base of the wall are open.
- Bare soil on a slope above a wall or parking area is a slide waiting for a saturating rain. Erosion blankets or hydroseed before November are cheap insurance.
5. Irrigation
The most common self-inflicted drainage problem we see is an irrigation controller still running a summer schedule in December.
- Switch controllers to a seasonal or rain-delay setting before the first storm.
- Confirm rain sensors or weather-based controllers are actually connected and working. Many aren't.
- Walk the system for broken heads and leaks. A leaking lateral on a slope saturates the soil long before the rain does.
6. Paving, walkways, and lighting
- Mark trip hazards and heaved sidewalk panels now. Wet leaves hide them in December.
- Confirm exterior lighting works. Storms arrive during the shortest days of the year, and your liability exposure goes up when a walkway is dark and wet.
- Check that parking lot striping and ADA paths are visible when wet.
7. Sandbags, pumps, and the emergency plan
- Know where water will go if a drain fails. Usually it's the lowest doorway on the property.
- Have sandbags or flood barriers on site for those doors, not in a warehouse across town.
- Keep a written list of who to call: your landscape contractor, a plumber for interior drains, and the county. SLO County and most cities publish sandbag locations each fall.
8. Documentation
- Photograph every problem area now, dated, before the rain. If a claim comes up in February, a before photo is worth more than any invoice.
- Keep vendor inspection reports with the property file. For HOAs, put the storm walk on the October board agenda and record it in the minutes.
9. The contractor conversation
If your landscape contractor hasn't walked the property with you this fall, ask them to. A good commercial landscape management partner should be able to tell you, in writing, which drains were cleared, which slopes were checked, and what they recommend before winter. If they can't, that's useful information too.
Frequently asked questions
When should a commercial property be inspected for storm readiness?
October, before the first significant rain. On the Central Coast that usually means getting it done by the end of October. Drains, slopes, and grading are easiest to evaluate when the ground is dry, and contractors still have availability.
Who is responsible for drainage maintenance on a commercial property?
In most cases the property owner, through their landscape or facilities contractor. Bioswales and detention basins built under a stormwater permit usually carry an ongoing maintenance obligation that stays with the property. Check your permit conditions or ask your contractor to confirm.
What does a free property walk from K&D include?
A site walk with one of our San Luis Obispo team members, a review of any areas where you have seen water problems before, and a one-page photo report of what we found. If you want options for repairs, we send a written proposal within a day. It is a visual assessment, not an engineering inspection.
Does El Niño mean the Central Coast will flood this winter?
No forecast can promise that. NOAA's outlook for winter 2026-27 leans toward wetter than normal conditions on the California coast, which shifts the odds but does not guarantee any single storm. The practical takeaway is that the cost of checking a property in October is small compared to the cost of a failed drain in January.
Want us to walk it with you?
Our San Luis Obispo team is doing a limited number of free property walks this fall for commercial properties, HOAs, wineries, schools, and churches from Paso Robles to Santa Maria. You get a one-page photo report of what we found, and a written set of options within a day if you want one. No pricing at the door and no obligation.
Request a free property walk
K&D Landscaping has been family owned on the Central Coast for 40 years. CSLB #664584.