Gutters, Downspouts, and Yard Drainage: A Pre-Rainy-Season Checklist for Foothill Homes
Water damage in foothill homes is almost never a plumbing problem. It is a drainage problem, and the fix is usually outside.
Written by the San Ramon Water Damage Pros crew — IICRC-certified technicians working to the ANSI/IICRC S500 standard on water losses across San Ramon and the Tri-Valley. Guidance here reflects how we actually run jobs, not general advice.
When we get called out during a storm to a hillside home in Bollinger Hills, Sycamore Heights, Round Hill or the Danville and Lafayette foothills, the cause is almost never the plumbing. It is drainage — a gutter, a downspout, an area drain or a grade that has settled.
All four are cheap to address and all four fail silently over the seven-month dry season. This is the checklist.
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- Clear them completely — not just the middle runs. Corners and the area immediately around downspout inlets clog first and are hardest to see from the ground.
- Flush with a hose afterward and watch that water actually reaches the downspout and exits at the bottom.
- Check the slope. Gutters should fall consistently toward the downspout; standing water in a gutter means it has sagged or the hangers have loosened.
- Look at the fascia behind the gutter for rot, which indicates it has been overflowing for a while.
- Consider gutter guards under heavy canopy — they are not maintenance-free, but they reduce the frequency considerably.
- Clear again mid-season, particularly after a wind event. In heavy-canopy neighborhoods a gutter cleaned in October can be full by January.
Downspouts
This is the item with the best return on effort in the entire checklist, and it is routinely wrong.
A downspout discharging at the base of a wall concentrates the entire roof catchment of that section into a small area of soil right against the foundation. During a sustained storm that is a very large volume in a very small place — and on expansive clay it also creates a permanently wet zone next to seasonally dry soil, which drives exactly the differential movement that cracks slabs.
- Extend discharge at least four to six feet from the foundation, further on a slope.
- Use solid extensions or buried drain lines rather than splash blocks, which do very little.
- If discharging into a buried line, confirm the outlet is clear — a buried line that is blocked is worse than no line, because water backs up against the foundation with no visible sign.
- Check that extensions have not been knocked out of place by landscaping, gardeners or weather.
- Make sure discharge does not simply run onto a neighbour’s property or into a path where it re-enters your lot.
Area Drains and Yard Drains
- Lift every grate and clear the basin. Sediment, leaf litter and root intrusion all accumulate silently over the dry season.
- Run a hose into each drain and confirm flow at the outlet. If water backs up in the basin, the line is blocked.
- Have blocked lines hydro-jetted rather than assuming they are beyond help — most clear readily.
- Check that the outlet daylights somewhere useful and is not buried under landscaping or silted closed.
- On a hillside, check upslope drains as well as those near the house. A blocked drain uphill sends its water to you.
- Re-check mid-season. Sediment washed down during the first storms is what clogs them for the second.
Grading and Hardscape
- Walk the full perimeter and look at how the ground meets the house. It should fall away — roughly six inches over the first ten feet is the conventional target.
- Look for settlement that has reversed the slope. This happens gradually over decades and is easy to miss.
- Check that landscaping, mulch and raised beds have not built the soil level up above the foundation weep screed or siding line.
- Look at patios, walkways and driveways for slope toward the house, and at joints where they meet it.
- On a hillside, look at the driveway specifically: does it channel surface water straight toward the garage?
- Check retaining wall weep holes and clear them — a wall with blocked weeps holds water against itself and against whatever is behind it.
The Test That Beats Every Inspection
Put a coat on and walk the perimeter during a heavy storm. Five minutes of watching where water actually goes tells you more than an hour of inspection on a dry day.
You will see the gutter overflowing at one corner, the downspout backing up, the spot where the patio sheds toward the wall, the area drain that has become a pond, and the low point where water pools against the garage. Those are your actual problems, in priority order, and none of them are apparent in October sunshine.
Photograph what you see. It makes the repairs concrete and it is useful documentation if water does get in.
What Blocked Drainage Costs, Ranked
Every item on a drainage checklist prevents something specific. Knowing what each one actually prevents makes it much easier to decide what to do first when there is not time to do everything.
- Blocked gutters overflow at the fascia, which puts water into the soffit and down the wall — the most common cause of exterior wall damage we attend.
- Downspouts discharging at the foundation deliver the entire roof area's runoff to one point beside the house, which is the leading cause of crawl space and lower-level seepage.
- Blocked area drains back up and pond, and a garage apron drain that has silted up sends the driveway's runoff into the garage.
- A blocked swale redirects flow that was being carried around the property, usually onto the lowest opening in the building.
- Reversed grading against the foundation puts water against the wall in every storm, and it develops invisibly as landscaping is topped up over the years.
- Blocked weep holes in a retaining wall make the wall hold water against itself, which turns a drainage problem into a structural one over a few seasons.
- A silted sump pit means the pump cannot lift what it was sized for, at the point of peak demand.
- Debris in a culvert under a driveway backs the whole upstream flow onto the property, and these are almost never inspected.
Frequently asked questions
At least four to six feet, and further on a slope. Splash blocks do very little — use solid extensions or a buried line, and if it is buried, confirm the outlet is actually clear. A blocked buried line is worse than none because water backs up against the foundation invisibly.
At least twice a season in a neighborhood with heavy canopy — once in October and again in December or January after wind has dropped more debris. Under mature oaks and sycamores, a gutter cleaned in autumn is frequently full by mid-winter.
Usually not. Most blocked drain lines clear readily with hydro-jetting, which is far cheaper than the water damage a blocked drain causes. The exception is root-invaded or collapsed line, which needs replacement — a camera inspection tells you which you have.
They reduce the frequency of clearing rather than removing the need for it, and under heavy tree cover they can trap fine debris on top where it is harder to remove than it would have been inside the gutter. Where they genuinely help is against large leaf litter on a roof that is awkward to access. Whatever you fit, still check the outlets — guards do nothing about a blocked downspout.
Put a hose in the top of it and watch the discharge point. Water should emerge quickly and at full flow. A weak trickle or a delay means an obstruction, usually at the first bend or where the line goes underground. It is a two-minute test per downspout and it finds problems that no visual inspection will.
The short version
Gutters cleared, downspouts extended, drains flushed, grading checked. Four items, one afternoon, and they prevent most of what we respond to.
Then walk the perimeter during the first real storm and fix whatever you see. That is the highest-value five minutes of the whole season.
