Persistent water in a floor drain can come from many causes—recent work, seasonal effects, pressure changes, or a blocked line. Use the short sections below to pick the scenario that best matches when and where the water appears so you can follow the right troubleshooting steps. For broader drain and basement topics, see Floor Drains, Basement & Main Lines.
After repairs, installations, and remodeling
These articles cover standing water that begins right after plumbing work, appliance installation, or construction. They explain what to check for debris, trapped air, or altered flow paths.
- Standing water after plumbing repair
Quick checks for leftover debris, displaced trap seals, or partially reassembled fittings that can leave the drain slow or standing.
- Standing water after remodel
How construction materials and changed floor slopes or drain connections can trap water, and simple inspection steps to find them.
- Standing water after filter install
What to look for when a new filter or bypass alters flow or leaves trapped debris, including valve and connection checks.
- Standing water after water heater install
Reasons water can pool after a heater swap—rerouted pipes, trapped sediment, or temporary air pockets—and how to rule them out.
- Standing water after sewer cleaning
Why jetting or snaking might temporarily reveal or redistribute blockages and what follow-up steps help confirm the real cause.
After outages, shutoffs, and pressure events
If standing water starts after a municipal outage, you turned water back on, or a pressure event occurred, these pages walk through likely valve and backflow issues. They focus on tests you can do without special tools.
- Standing water after city outage
How pressure loss and debris from the mains can let water sit in drains, and practical flushing and inspection steps to try first.
- Standing water after turning water back on
Explains air, dislodged sediment, and partially open valves as common culprits and what to check to restore normal flow.
- Standing water after smart shutoff trip
Describes how automatic shutoff devices can leave trapped pockets or change pressures that produce standing water and how to reset or test them.
- Standing water after vacation
Issues from extended idle plumbing—settled debris, weakened seals, or minor blockages—and simple steps to refresh drains after return.
- Standing water after pressure change
How sudden pressure shifts can expose weak traps, vents, or seals and what to observe to determine if pressure is the cause.
Seasonal and temperature-related issues
Cold weather and winter prep can introduce unique causes for standing water. These articles help distinguish freezing, thawing, and seasonal maintenance effects.
- Standing water after winterization
What winterizing steps can leave residual water or trapped pockets in drains, and how to safely clear them when warming up.
- Standing water only in winter
Signs that ice, frozen vents, or thaw cycles are the cause and how to check without risking damage to pipes or finishes.
- Standing water only at night
Why temperature drops or nighttime pressure changes can make standing water visible after dark and what to monitor.
Location- and timing-specific problems
When the issue is limited to one drain, tied to an appliance, or getting worse over time, the likely causes differ. These pages show focused diagnostics to narrow the problem.
- Standing water only in one drain
Steps to compare drains, test for a local clog or trap issue, and spot slope or grate problems that trap water.
- Standing water only when washer runs
How washer discharge, partially blocked standpipes, or shared line backflow create temporary pooling and what to inspect.
- Standing water in basement drain
Basement-specific causes like sump interaction, low mainline grade, or municipal backflow and when to escalate the issue.
- Water never moves in floor drain
Diagnostics for a completely stagnant drain—venting, dried or blocked trap, or severe obstruction—and simple tests to try first.
- Standing water worsens over time
Signs of progressive problems such as accumulating debris, root intrusion, or failing venting and guidance on when to involve a pro.
All Articles in This Cluster
- Standing water in basement drain
- Water never moves in floor drain
- Standing water after plumbing repair
- Standing water after city outage
- Standing water after winterization
- Standing water only in winter
- Standing water after remodel
- Standing water after pressure change
- Standing water only when washer runs
- Standing water after turning water back on
- Standing water after filter install
- Standing water after smart shutoff trip
- Standing water after vacation
- Standing water after water heater install
- Standing water only at night
- Standing water only in one drain
- Standing water after sewer cleaning
- Standing water worsens over time