Pre-install safety check: Is the existing pit dry (or can you fully bail it), and is there a GFCI-protected dedicated outlet within reach of the pump's cord without an extension?

Sump pumps must plug into a GFCI outlet within cord-reach. Never use an extension cord. If the pit is full of standing water and the existing pump is dead, unplug it before reaching in.

Inspect the discharge line. What does it look like, and where does it terminate?

Code-compliant discharge is rigid PVC (typically schedule 40, 1.5" or 1.25") that exits the foundation and either daylights well away from the house, ties to a storm sewer, or runs to a dry well. It must NEVER connect to the sanitary sewer.

Are you installing a primary pump only, or primary plus a battery backup?

Battery backup pumps mount in the same pit and trigger when the primary fails or power is out. DIY install is reasonable for handy users; the battery and charger sit nearby on the floor.

Are you sizing a new pump based on basement depth and rainfall, or doing a same-for-same replacement of a known-good size?

1/3 HP handles most homes with shallow basements and average rainfall. 1/2 HP is the right call for deep basements (>8 ft lift), high water tables, or heavy regional rainfall. Same-for-same is the lowest-risk DIY path.

plumbing troubleshooting

Install sump pump

Common symptoms: new sump pump install; sump pump replacement; basement water management; battery backup pump; discharge line routing

Stop and call a pro if:

electrical near water — GFCI required
do not connect discharge to sanitary sewer
lifting heavy pumps and pits

Step-by-step diagnostic flow

Step 1
Pre-install safety check: Is the existing pit dry (or can you fully bail it), and is there a GFCI-protected dedicated outlet within reach of the pump's cord without an extension?
Sump pumps must plug into a GFCI outlet within cord-reach. Never use an extension cord. If the pit is full of standing water and the existing pump is dead, unplug it before reaching in.
Step 2
Inspect the discharge line. What does it look like, and where does it terminate?
Code-compliant discharge is rigid PVC (typically schedule 40, 1.5" or 1.25") that exits the foundation and either daylights well away from the house, ties to a storm sewer, or runs to a dry well. It must NEVER connect to the sanitary sewer.
Step 3
Are you installing a primary pump only, or primary plus a battery backup?
Battery backup pumps mount in the same pit and trigger when the primary fails or power is out. DIY install is reasonable for handy users; the battery and charger sit nearby on the floor.
Step 4
Are you sizing a new pump based on basement depth and rainfall, or doing a same-for-same replacement of a known-good size?
1/3 HP handles most homes with shallow basements and average rainfall. 1/2 HP is the right call for deep basements (>8 ft lift), high water tables, or heavy regional rainfall. Same-for-same is the lowest-risk DIY path.

Possible outcomes

Stop — electrical hazard in flooded pit

high confidence

A dead pump in a flooded pit may still be energized through a fault. Do not reach into standing water until the circuit is killed at the breaker.

Safe next steps

Kill power at the breaker panel, not just by unplugging
Verify with a non-contact voltage tester before reaching in
Bail standing water with a bucket and shop vac before pulling the old pump
Then restart this workflow from the top

Energized water risk

Install GFCI outlet first — call an electrician

high confidence

Code requires GFCI protection within cord-reach for sump pumps. Extension cords are not acceptable. Get the outlet in before pump work.

Safe next steps

Have an electrician install a dedicated 15A or 20A GFCI receptacle within 6 ft of the pit
Confirm it's on its own circuit (sump pump should not share with freezer or other large loads)
Then return to this workflow

What to document for a pro

Distance from pit to nearest panel run
Existing panel capacity

Discharge tied to sanitary sewer — separate before reinstalling

high confidence

Sump discharge into the sanitary sewer is prohibited in nearly every US jurisdiction — it overloads the treatment plant and often causes basement backups during storms. This needs to be corrected before any pump install.

Safe next steps

Do not reinstall a pump on this discharge — every gallon you pump becomes a sewer surcharge problem
Plan a new discharge route: out through the rim joist or foundation wall to daylight at least 10 ft from the foundation
Check with your municipality — many offer rebates for sanitary-to-storm sump separations
Hire a plumber for the foundation penetration and exterior trenching

What to document for a pro

Photo of current sanitary tie-in
Distance to property line on the discharge side

Same-for-same replacement — proceed

high confidence

Replacing a known-working pump with the same HP and discharge size is the most predictable DIY sump job. The pit, discharge route, and electrical are already proven.

Safe next steps

Unplug old pump at the GFCI outlet
Cut the discharge pipe just above the existing check valve (or unscrew the union if present)
Lift old pump out — wear gloves, expect it to be heavy and dirty
Test-fit new pump in the pit; confirm float switch has clearance to rise and fall without hitting the pit wall
Install new check valve on the pump's discharge nipple, oriented arrow-up
Install a union above the check valve so future replacement is easier
Re-glue or thread into the existing discharge stub
Plug into GFCI; pour 5 gallons of water into the pit to trigger the float and verify pump-out cycle
Confirm the check valve thumps closed (you'll hear it) and water doesn't drain back into the pit

New install — proceed if you have GFCI, exterior discharge path, and plumbing skill

medium confidence

First-time installs include pit prep, foundation penetration, and exterior grading — meaningfully more work than a swap, but DIY-feasible for handy users.

Safe next steps

Verify pit depth (18" min, 24"+ preferred) and diameter (18" preferred for full-size pumps)
Add 2-3" of clean gravel to the pit bottom for the pump to sit on
Drop pump in; mark and cut discharge pipe to length
Assemble: pump nipple → check valve (arrow-up) → union → vertical run to rim joist or foundation
For foundation penetration: drill with a hammer drill + masonry bit, sleeve with PVC, seal with hydraulic cement
Exterior: pipe must slope away from foundation, terminate min 10 ft from the house, and not point at a neighbor's yard or back at your own slab
In freeze zones: include an above-grade air gap or IceGuard fitting so the pump can still discharge if the buried line freezes
Plug into GFCI; test with 5 gallons of water; check for leaks at every joint
Check local code — some jurisdictions require a permit for new sump installs

What to document for a pro

Photos of pit and proposed discharge exit point
Rainfall zone / water table notes

Get a pro to size and spec the install

low confidence

If sizing is unclear, the install itself is probably the wrong place to learn. Wrong HP wastes power and short-cycles the pump; undersized HP floods the basement.

Safe next steps

Have a plumber or waterproofing contractor walk the basement, measure pit depth, and estimate inflow
Ask for written sizing rationale (HP, GPH at your specific head height) so you can DIY future swaps
If you want to DIY the labor, ask if they'll sell you the spec'd pump and you install

What to document for a pro

Basement depth below grade
Regional rainfall / known water table issues
History of past flooding

Diagnostic guidance only. If unsure, stop and call a licensed professional — gas, electrical, and refrigerant work is hazardous to untrained users.

Pro launch updates

Get notified when Pro launches, plus a monthly code-change digest. Email only — no account required.