Sump Pump vs. French Drain: Which Solves Your Water Problem?

Gravity First, Pump Only When You Must

When water keeps showing up where it shouldn't, two solutions dominate the conversation: a French drain and a sump pump. They're often pitched as competitors, but that framing misses the point. They're not really alternatives — they answer a single question: can gravity carry this water away on its own, or does it need a lift? French drains rely on gravity. Sump pumps exist for when gravity can't do the job.

Understanding that distinction tells you which one your Oregon property actually needs — and why the answer should usually start with the drain. For the full set of options, see our Oregon drainage guide.

The French Drain: Gravity Does the Work

A French drain collects water and moves it to a lower outfall using nothing but slope. Water seeps into the gravel trench, drops into the perforated pipe, flows downhill to a daylight point, dry well, or permitted connection, and exits. No power, no moving parts, nothing to fail or maintain mechanically.

That's the beauty of a gravity drain: once it's built right, it just works, quietly, for decades. The requirement is a viable outfall lower than the collection area. On sloped Oregon lots, that's usually available, and a French drain is the clear first choice. Our French drain cost in Oregon guide covers it.

The Sump Pump: Lifting Water Uphill

A sump pump sits in a pit (the sump) at the low point of a basement or drainage system. Water collects in the pit, a float switch trips, and the pump lifts it up and out through a discharge line to somewhere it can drain away. The key word is up. A pump exists to move water in a direction gravity won't take it.

You need a pump when there's no gravity outfall available — a basement floor below the surrounding grade, a flat lot with no lower ground to reach, or a high water table that has to be actively pumped down. The trade-off is real: a pump is a mechanical device that needs power, can fail, and may need a battery backup for the storms that knock out electricity exactly when you need it most.

The Real Question: Is There a Gravity Outfall?

Everything comes down to this. Walk the site and ask whether water collected at the problem area can reach a lower discharge point by gravity alone:

• Yes, there's lower ground or a viable connection → a French drain (or footing drain) carrying water to that outfall. Gravity, no pump. Our how to daylight a drain guide covers finding the outfall.
• No — the water is below any possible outfall, or the lot is dead flat → a sump pump to lift the water out.

This is why the same wet-basement problem gets a French drain at one house and a sump pump at the next: the difference is the geography of the outfall, not the severity of the water.

Interior vs. Exterior, and Where Each Fits

The French-drain-versus-sump-pump choice overlaps with an interior-versus-exterior one:

• Exterior drainage — a footing drain outside the foundation, ideally draining by gravity — stops water before it reaches the wall. It's the preferred approach when a gravity outfall exists. See our foundation drain installation cost guide.
• Interior drainage with a sump pump — a drain inside the basement perimeter feeding a pit, with the pump lifting water out — handles water that has already reached the wall, and is often the practical answer when exterior gravity drainage isn't possible.

Frequently the best system combines them: exterior gravity drainage where it can keep water out, backed by an interior sump pump for what still gets in or for the high-water-table situations a gravity drain can't address.

Why a Pump Is a Last Resort

A sump pump is a great tool, but it adds a point of failure. Power goes out, floats stick, motors wear, discharge lines freeze. A gravity French drain has none of those vulnerabilities. So the design principle is simple: use gravity wherever the site allows it, and reach for a pump only when the geography genuinely forces water uphill. When you do need a pump, a battery or water-powered backup is worth it for Oregon's storm-season outages.