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Quick answer from a licensed plumber: A French drain carries water away by gravity through a perforated pipe in a gravel trench; a sump pump lifts water out of a pit. Yard puddles call for grading, gutters or a French drain. Water seeping into a basement usually needs drain tile at the footing that empties into a sump pit with a pump. Many basements use both.
If you need the pump side: the Wayne CDU790 for a typical pit, or the CDU980E for heavy inflow. Check the Wayne CDU790 on Amazon
People ask which one to buy as if they were rivals. They are not. A French drain is a trench with a perforated pipe that carries water away by gravity. A sump pump is a powered pump that lifts water out of a pit. The real question is where the water is and where it has to go. This page sorts that out from an extension service, two makers’ manuals and NDS, then lists the parts we would look at on Amazon.
French Drain vs Sump Pump at a Glance
| French drain | Sump pump | |
|---|---|---|
| What it is | A gravel-filled trench with a perforated or slotted pipe (NDS) | An automatic pump in a pit that removes water that has collected there (Wayne) |
| How the water moves | By gravity, down a sloping pipe to an outlet (NDS) | Lifted by the pump to a discharge pipe outside the foundation (Minnesota Extension, Wayne) |
| Where it works | Yards, patios, retaining walls, foundations, crawl spaces (NDS) | A basement or crawl space pit, most commonly for basement drainage (Wayne) |
| Runs on | Slope and gravity | Electricity from a GFCI-protected receptacle (Wayne) |
| Where the water ends up | A daylight outlet, dry well or infiltration area (NDS) | A discharge point at least 3 ft from the foundation (Wayne) |
| What goes wrong | Clogging from fine soil, clay or tree roots (NDS, Minnesota Extension) | Stuck float, failed switch, clogged inlet, power loss (Wayne, Zoeller) |
| Upkeep | Keep the outlet clear and the fabric intact; watch for pooling | Test every few months; replace a tether switch every two years (Zoeller, Wayne) |
Both are described from the sources listed at the bottom of the page. The NDS entries come from a French drain maker’s guide, so read its claims as the maker’s view.
What Each One Actually Does
A French drain is a trench with a perforated or slotted pipe at the bottom and gravel around it. NDS says it collects water along its whole length, not at one spot, and sends it to a lower place: a daylight outlet, a dry well or an infiltration area. Gravity does all the work, so the pipe has to slope. NDS also says that clay can clog the gravel with fine particles, which is why NDS describes wrapping the pipe and gravel in filter fabric.
A sump pump handles the last step. Water collects in a pit in the basement floor, a float switch turns the pump on at a set level, and the pump pushes the water out through a discharge pipe. Wayne says sump pumps are for clear water only, need a check valve and rigid pipe, and should have an independent high water alarm or a backup pump where high water could cause damage. Minnesota Extension adds that the pit should have an airtight, childproof cover, because an open pit draws moist air into the house.
Which One Do You Need?
Start with the roof and the grade. Minnesota Extension says a great number of basement water problems come from rain and surface water, and that gutters, downspouts and grading should be fixed before any below-grade drain. Its numbers: slope the ground away from the foundation at least 1 inch per foot for at least 6 feet, one downspout per 50 linear feet of eave, and downspout extensions that discharge at least 4 feet beyond the wall. It also says summer condensation is often mistaken for wall leakage. NDS, which sells French drains, says a musty smell or wet basement floor means you need one immediately. The extension service’s order of work is the safer one to follow.
Puddles in the yard, a soggy lawn, water pooling at a patio: that is surface and shallow soil water, and it is what a French drain is built for. NDS suggests watching where water sits for hours or days after a rain to site the drain. No pump is involved if the ground slopes to a place the water can leave.
Water seeping at the basement wall or floor: Minnesota Extension says that if grading and gutters do not solve it, the next step is an interior or exterior drainage system, and both connect to a sump. Exterior drain tile at the footing is the most effective and the most costly, because it means digging up the foundation. Interior systems collect the water inside and drain it to the sump. Either way the sump pump is what moves the water out of the house.
A high water table: Minnesota Extension says the water table can rise with flooding or seasonal conditions, which is why it recommends drain tile around basement walls even in sandy or gravel soils. It also warns that an interior system under the slab cannot take in rising groundwater in low-permeability soil unless there is an aggregate layer under the slab. This is the case for a professional’s assessment.
Only a sump pit, no drain tile: the pump works only on the water that reaches the pit. Minnesota Extension notes that many older houses have no subsurface drainage system at all, and that failed systems are usually a collapsed pipe, silt or roots, or a broken connection to the sump.
Why They Are Often Installed Together
Wayne’s typical sump installation drawing labels a “drain tile outlet” alongside the basin, check valve, gasketed basin lid and vent pipe. That is the standard basement setup: drain tile at the footing collects the water and the sump pit and pump remove it. A yard French drain is a separate system that keeps surface water from ever reaching the foundation, and it can run entirely on gravity. If your yard drain outlet sits in a low spot next to the house, it may feed the same problem; NDS says to put the outlet at the lowest point, away from buildings.
Parts You Can Buy on Amazon
| Part | Type | Maker’s flow rating | Source |
|---|---|---|---|
| Wayne CDU790 | Sump pump, 1/3 HP | 3,060 gal/hr at 10 ft of lift; 2,220 at 15 ft | Wayne manual |
| Wayne CDU980E | Sump pump, 3/4 HP | 4,600 gal/hr at 10 ft of lift; 4,100 at 15 ft | Wayne manual |
| NDS pop-up emitter | French drain outlet | Up to 56 GPM | NDS emitter page |
Flow figures are copied from Wayne’s manual table and NDS’s emitter page. Each linked item was listed in stock and shipped and sold by Amazon.com when we checked on September 28, 2026. We did not link the Zoeller M53 or a perforated pipe with sock because none met that test when we checked.
Wayne CDU790 1/3 HP Submersible Sump Pump
1/3 HP · 120 V, 60 Hz · 15 A circuit minimum · coated steel motor housing, cast iron volute · vertical float switch per the Amazon listing · Wayne lists 4,600 gal/hr at 0 ft of lift and 2,220 at 15 ft · indoor use only · 3-year limited warranty
The CDU790 is Wayne’s 1/3 HP pit pump. Wayne’s table gives 4,600 gallons per hour at no lift, 3,810 at 5 feet, 3,060 at 10 feet, 2,220 at 15 feet and 1,200 at 20 feet. Those figures fall fast with height, so measure how far the water has to rise from the pit to where your discharge pipe exits before you trust the headline number.
Wayne’s manual is clear about what a sump pump is for: it says these pumps remove ground water from sump pits, most commonly for basement drainage, and that they are for clear water only. It requires a check valve and rigid discharge piping, a GFCI-protected receptacle, and a discharge that carries water at least 3 feet from the foundation. It also asks for an independent high water alarm or a backup pump wherever high water could cause property damage. The Amazon listing says the top-suction design removes the need for a weep hole; the manual itself does not mention one, and Zoeller’s instructions for its own pumps recommend a vent hole when a check valve is used, so read the manual that ships with the pump.
- Wayne publishes flow at 0, 5, 10, 15 and 20 feet of lift, so you can size it to your discharge height
- Sold and shipped by Amazon.com
- Manual spells out the check valve, rigid pipe, GFCI and 3-foot discharge requirements
- Three-year limited warranty, per Wayne
- Flow drops to 1,200 gal/hr at 20 feet of lift, per Wayne’s table
- Coated steel motor housing rather than the stainless steel on the CDU980E
- A basin, check valve and discharge pipe are bought separately, per the manual
- Not designed for use with a portable generator, per Wayne
Verdict: A sensible pump for a typical residential pit with moderate inflow and a short lift to the discharge pipe.
Wayne CDU980E 3/4 HP Submersible Sump Pump
3/4 HP · 120 V, 60 Hz · 15 A circuit minimum · stainless steel motor housing, cast iron volute · vertical float switch per the Amazon listing · Wayne lists 5,490 gal/hr at 0 ft and 4,100 at 15 ft · indoor use only · 5-year limited warranty
The CDU980E is the 3/4 HP step up in the same Wayne manual. Wayne’s table gives 5,490 gallons per hour at no lift, 5,076 at 5 feet, 4,600 at 10 feet, 4,100 at 15 feet and 3,500 at 20 feet. At 15 feet of lift that is nearly twice the 2,220 the CDU790 lists (our arithmetic: 4,100 divided by 2,220 is about 1.85). This is the one to look at if your pit fills quickly during a storm or the discharge pipe has to climb.
The same rules apply. Wayne says to set the pump on a solid, level surface and not directly on clay, earth, gravel or sand, to keep the float clear of the basin wall, and to secure the basin cover to keep debris out and contain gases and odors. Its routine maintenance section says to inspect the pump three to four times a year and to pour a bucket of water into the pit to confirm it starts and drains. The higher flow does not replace a backup: a pump only helps while it has power, and Zoeller’s instructions say to consider a D.C. backup system where power loss could cause flood damage.
- Higher flow than the CDU790 at every lift Wayne lists: 4,100 vs 2,220 gal/hr at 15 feet
- Stainless steel motor housing, per Wayne’s manual
- Five-year limited warranty, per Wayne
- Sold and shipped by Amazon.com
- Still needs a check valve and rigid pipe, bought separately, per Wayne
- Indoor use only and not for use with a portable generator, per Wayne
- Needs a basin at least 22 inches tall, per Wayne’s drawings
Verdict: The pick for a pit with heavy inflow, a long lift, or a house where you want the longer warranty.
NDS Pop-Up Drainage Emitter with Elbow for 4 in. Pipe
Fits 4 in. sewer and drain pipe and 4 in. triple-wall pipe · spring-loaded HDPE cap opens as high as 1 in. · NDS lists up to 56 GPM · PVC elbow with weep hole · Amazon lists it as model 422G
A French drain has to end somewhere. NDS says every drainage system needs a point of release for collected water, and its pop-up emitter is that end point: the spring-loaded cap lifts as high as 1 inch when water pressure builds and drops shut as the flow eases, which NDS says keeps debris and rodents out of the pipe. A small weep hole in the elbow drains water left in the pipe so it does not sit or freeze in cold weather.
NDS says to install the emitter at the lowest point in the drainage system, away from buildings, landscaped areas and poor drainage areas. That matters: putting the outlet near the house sends the water straight back to where it started. NDS’s website lists this design as model 421 in its catalog; the Amazon listing calls it 422G with the same description, and we could not find a cross-reference on NDS’s pages, so match the pipe size on the package. The emitter is only the outlet: the pipe, fabric and gravel are separate parts (NDS also makes a pre-wrapped EZflow pipe). The NDS Flex-Drain 4 in. pipe with sock showed no available offer on Amazon when we checked, so we did not link one.
- Cap stays closed when not draining, keeping debris and rodents out, per NDS
- Weep hole in the elbow drains the pipe, per NDS
- Flange is designed to keep grass from growing over the cover, per NDS
- Sold and shipped by Amazon.com
- Only the outlet: pipe, fabric and gravel are separate
- Fits 4 in. pipe; other sizes need adapters, per the Amazon listing
- Amazon and NDS use different model numbers for what reads as the same part
Verdict: The right finish for a yard French drain or a downspout line that daylights at the lowest point of your lot.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
What Drives the Cost
We do not quote prices on this site, so here are the drivers instead. For a French drain, NDS lists pipe, aggregate, fabric, couplers and end caps, plus permits, fees, equipment rental (a trencher or compactor) and labor. For drainage around a basement, Minnesota Extension ranks the options: an exterior system at the footing is the most costly and most effective; an interior channel on top of the slab is the simplest and least costly, but it does not drain groundwater from under the slab and does not fix block walls; an interior channel in the slab edge or a pipe under the slab means breaking and replacing concrete. For the pump side, the basin is bought separately, and the check valve, rigid discharge pipe, a GFCI receptacle wired by an electrician and a backup pump or alarm all add to the pump itself (Wayne, Zoeller).
Maintenance
Sump pump: Zoeller says to inspect and test the system at least every three months. Wayne says to check the pump three to four times a year for movement or debris on the float, pour a bucket of water in to confirm it starts and drains, clear the inlet screen, make sure the GFCI has not tripped, and replace a tether switch every two years. Zoeller says to check any vent hole in the discharge pipe periodically for clogging. See sump pump check valves and battery backup sump pumps.
French drain: The threats are clogging and a blocked outlet. NDS says clay can push fine particles into the gravel and block the flow, and Minnesota Extension lists pipe collapse, silt and tree roots as reasons drain tile stops working. A pop-up emitter with a weep hole, per NDS, drains the pipe after a storm so water does not sit or freeze inside it. Watch for new pooling after a rain, which is the first sign the drain is not keeping up.
When to Call a Waterproofing Contractor
- Digging next to the foundation. Minnesota Extension says exterior drainage means digging up the area around the foundation and rebuilding it like a new house, usually with waterproofing and insulation done at the same time.
- Breaking the slab. Interior drain pipe or channel at the footing means removing and replacing concrete, and in block walls holes are drilled at the base of every core. That is contractor work in our view.
- Cracks or a settling foundation. Minnesota Extension says drainage usually removes the water from cracks but some may need structural repair.
- A wet, finished basement or standing water that keeps coming back. The extension service says to deal with the water problem before finishing a basement.
- Wiring and locates. Wayne says all wiring must be done by a licensed electrician, and NDS says to have the local utility mark underground lines before digging and to check city codes and how a drain affects the neighbors.
In our view a gutter, grading or yard French drain job is a reasonable do-it-yourself project, and anything at the footing or under the slab is not.
FAQ
Can a sump pump replace a French drain?
They do different jobs, so not really. A sump pump removes water that has collected in its pit; Wayne describes it as a pump for removing ground water from sump pits. A French drain is what carries water to a pit or away from an area in the first place. The University of Minnesota Extension notes that many older basements have no subsurface drainage at all, and that where a drain tile system exists, it fails when the pipe collapses, clogs with silt or tree roots, or loses its connection to the sump.
Do I need both a French drain and a sump pump?
For a wet basement, often yes. Minnesota Extension says every exterior drainage system it describes drains to a sump that can be pumped out, and that an interior perimeter drain pipe connects to the sump as well. For yard drainage, NDS says a French drain can run to a daylight outlet, a dry well or an infiltration area, so no pump is needed if the ground slopes away.
Where should a sump pump discharge?
Wayne says the discharge pipe must carry water to a point at least 3 feet from the foundation, and that a pipe exposed to freezing should slope down and away from the house so it drains. Minnesota Extension says downspout extensions should discharge at least 4 feet beyond the wall. See our guide to sump pump discharge freezing.
How deep does a French drain need to be?
NDS says about 8 inches to 2 feet is enough for many water-diverting projects, and that systems around foundations or below-grade rooms may go deeper. Its guide gives more than one slope figure: a 2 percent minimum for corrugated pipe is one expert recommendation, and it says in general a French drain should drop at least 1 percent. Ask your installer which applies to your pipe.
How often should I test a sump pump?
Zoeller says to inspect and test the system at least every three months. Wayne says to inspect it three to four times a year, pour a bucket of water into the pit to confirm it starts, check the inlet screen, and replace a tether switch every two years. If yours is not starting, see sump pump not working.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber. Every size, rating, dimension and spec on this page comes from the manufacturer pages and documents listed below, which we opened and read, or from the Amazon listing we link; nothing here comes from hands-on testing. Each linked product was shipped or sold by Amazon, new and in stock, when we checked on September 28, 2026. Where a link goes to Amazon we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- University of Minnesota Extension: Moisture in basements, causes and solutions
- NDS: French drain installation guide
- NDS: pop-up drainage emitter with elbow for 4 in. drain pipes (model 421)
- Wayne: submersible sump pumps operating instructions and parts manual (600002W-001 J)
- Zoeller: installation instructions for the 53, 57 and 98 series (FM2676)
- Amazon listings for the Wayne CDU790 and CDU980E and the NDS pop-up emitter (linked above)
Bottom Line
Fix the roof water and grading first; that is the extension service’s advice and it costs the least. For yard water, a French drain with a proper outlet is the tool. For water at the basement walls or floor, drain tile at the footing feeding a sump pit and pump is the standard answer, and the work at the footing is a contractor job. Buy the pump for your lift and inflow, add a check valve and a backup, and test it every few months.