Ravenna sits on the slopes above a wooded ravine, and anyone who has walked the trail through Ravenna Park after a week of November rain knows how much water moves through this part of north Seattle. The creek at the bottom of the ravine is the part you can see. The part you can't see is the groundwater that seeps through the hillsides and into the soil around the houses on the streets above it.
That matters most to people who own the older homes here. A lot of Ravenna's housing went up in the early twentieth century: Craftsman bungalows, boxy foursquares and a scattering of brick Tudors, many with full or partial basements dug long before anyone thought much about perimeter drains or vapour barriers. Plenty of those basements have since become bedrooms, home offices or small rental units, which raises the stakes when water finds a way in.
How water usually gets into a Ravenna basement
It is rarely a dramatic flood. More often it is a damp corner that never quite dries, a chalky white line along the base of a concrete wall, or a thin film of water that turns up under a rug after a long storm. Older foundations in the neighbourhood were often poured with little in the way of drainage, and the original clay drain tile around some houses has long since cracked, silted up or been crushed by roots from mature street trees.
Lots on the slopes dropping toward the ravine and Cowen Park tend to have the hardest time. Water moving downhill underground meets the uphill wall of the foundation and has nowhere else to go. Houses on the flatter blocks toward Roosevelt aren't immune either; a high water table through the wet months can push moisture up through the slab itself.
Where a sump pump fits in
A sump pump does a simple job. Water collecting beneath or around the basement floor drains into a pit, and when the level rises, a float switch turns the pump on and sends the water out through a discharge line, away from the foundation. It doesn't stop water reaching the house. It gives that water somewhere to go other than across your floor.
For a lot of Ravenna homes the pump is one piece of a larger fix. An interior drain channel cut along the edge of the slab can collect seepage from the walls and carry it to the pit. Outside, regrading the soil so it falls away from the house and making sure downspouts empty well clear of the foundation can reduce how often the pump runs at all. The right order depends on where the water is really coming from, which is why a careful plumber spends time looking before quoting anything.
Details that are easy to get wrong
Where the discharge ends up is the first one. Pumping water onto a slope that drains straight back toward the house just sets up a loop. On narrow Ravenna lots with neighbours close on both sides, the outlet also has to go somewhere that won't send water into the yard next door. Seattle has rules about what can and can't be connected to the sewer, so ask how the plumber plans to handle the outlet rather than assuming.
Power is the second. The worst storms here tend to arrive with wind, and wind brings down branches and lines, especially on streets shaded by big old trees. A pump that quits when the power does isn't much protection on the night it matters. A battery backup, or a water-powered backup where household pressure allows, is worth talking through.
The third is the pit and the check valve. A pit that is too small makes the pump cycle on and off constantly and wears it out early. A missing or failed check valve lets the water sitting in the discharge line fall back into the pit after every cycle. Neither costs much to get right at the start, and both are a nuisance to fix later.
Finished basements and older wiring
Turning a basement into living space changes the calculation. Carpet, drywall and furniture turn minor seepage into a real loss, so many owners put a pump in before finishing the space rather than after the first soggy winter. Older houses in the neighbourhood also tend to have basement wiring that predates current standards, so the pump belongs on a properly grounded, GFCI-protected outlet, not an extension cord run to whichever outlet is closest. If a damp lower floor is the bigger worry, there's more here on keeping a below-grade room dry.
Working with someone who knows the area
Because so much depends on the lot, the age of the foundation and how the house has been altered over the decades, it helps to work with someone familiar with the neighbourhood's housing. A plumber who has been in plenty of Ravenna basements will recognise the usual patterns: the slope-side seep, the cracked tile drain, the downspout emptying right beside the wall. For neighbourhood plumbing help, including drainage and basement water problems, see www.plumberseattle.us.com/plumber/ravenna.
Before work starts, ask what they think the water source is, where the discharge will go, whether a backup is included and how the pit will be covered. After that, keep an eye on it. Pour a bucket of water into the pit each autumn before the rain settles in and make sure the pump kicks on and empties it. There's a separate piece on heading off basement flooding before the wet season that goes further into that kind of routine check.
The ravine is one of the reasons people love living in Ravenna. A little planning below the floorboards keeps the water that carved it outside, where it belongs.