What Is a Stormwater Catch Basin and How to Keep It Clean

A stormwater catch basin is a covered structure that collects rainwater and runoff from streets, parking areas, sidewalks, and other paved surfaces. You may recognize it as a metal grate set into the roadway or along a curb. Beneath the grate, a chamber captures water and allows heavier sediment and debris to settle before runoff continues through the drainage system.

These structures help prevent standing water, street flooding, and damage to pavement. They also direct rainwater away from homes, businesses, and public facilities. In Susanville, properly functioning storm drains are an important part of maintaining safe streets and reliable municipal infrastructure.

Keeping a catch basin clear is a shared responsibility. City crews inspect and maintain public drainage facilities, while residents and property owners can reduce blockages by keeping nearby grates free of leaves, litter, mud, and other materials.

How A Catch Basin Works

When rain reaches a paved surface, it flows downhill toward the lowest available point. The grate over a catch basin allows water to enter while helping prevent large objects from dropping into the underground pipe network. Inside the basin, sediment and heavier particles may settle at the bottom.

The water then leaves through an outlet pipe and continues toward a storm drain, channel, detention area, or another approved drainage facility. Unlike wastewater from sinks and toilets, stormwater generally receives little or no treatment before entering local waterways. That makes preventing pollution at the source especially important.

A catch basin is sometimes called a storm drain, but the terms are not always interchangeable. The grate is the visible inlet, while the catch basin is the chamber below it. Together, these components form part of a larger stormwater drainage system.

Why Clean Storm Drains Matter

Leaves, grass clippings, trash, gravel, and soil can cover a grate or fill the basin. During a storm, this material can slow the flow of water and cause ponding around intersections, driveways, sidewalks, and building entrances. A blocked inlet may also allow runoff to travel across a roadway instead of entering the drainage system.

Pollutants can create a second problem. Motor oil, antifreeze, pesticides, paint, pet waste, and other contaminants may be carried by rainwater into storm drains. Because stormwater can move quickly, a small amount of pollution near a grate may affect a much larger area downstream.

Residents can find municipal infrastructure information and department contacts through the Susanville Public Works website. Reporting a damaged grate, unusual discharge, or recurring flooding early can help the appropriate department assess the problem before it becomes more serious.

What Belongs Near A Catch Basin

Routine care begins with simple observation. Before a forecasted storm, check the grate near your home or business if it is safe to do so. Remove loose leaves and small amounts of surface debris from the grate, placing the material in the appropriate waste or yard-waste container.

Never sweep dirt, leaves, grass, or trash into the opening. Do not pour liquids into a storm drain, even if the liquid appears harmless. Water from washing vehicles, cleaning equipment, or rinsing patios may carry soap, sediment, metals, and other pollutants into the drainage network.

Material or activity	Recommended action
Leaves and loose litter on the grate	Remove safely and dispose of properly
Mud, gravel, or a deep sediment buildup	Report it for assessment and cleaning
Motor oil, fuel, or chemicals	Keep away from drains and report a spill
Paint, solvents, or pesticides	Use approved disposal options
Damaged, missing, or unstable grate	Keep people away and contact Public Works
Snow or ice blocking drainage	Clear only when safe; avoid pushing debris into the inlet

Safe Ways To Maintain The Area

Light surface cleanup may be appropriate for a property owner when the grate is stable, traffic is not nearby, and weather conditions are safe. Wear gloves and sturdy shoes, use a rake or broom, and keep children and pets away from the work area. If the grate is in a roadway or requires lifting, leave it to trained personnel.

Do not enter a catch basin or attempt to climb inside an underground drainage structure. These spaces may contain contaminated water, unstable sediment, sharp objects, or hazardous gases. Avoid using pressure washers or hoses to force debris into the system, since that can move pollutants farther downstream and create a blockage in the pipe.

Household chemicals should never be emptied into a storm drain. Review the city’s household hazardous waste guidance for safer handling and disposal information.

Signs A Catch Basin Needs Attention

Some warning signs are visible before a drainage failure occurs. Water that remains on the street long after rainfall, bubbling at a grate, a strong chemical odor, or sediment piled around the inlet may indicate a blockage or damaged component. A grate that is cracked, loose, sunken, or missing also requires attention.

Do not remove a grate to inspect the basin yourself. Keep a safe distance from fast-moving water and traffic, especially during a storm. If flooding is threatening a structure, roadway, or utility service, use the appropriate emergency contact rather than attempting a risky cleanup.

Helpful Steps For Property Owners

• Check nearby grates before and after major rain, without entering the roadway.
• Keep leaves, grass clippings, soil, and construction materials away from drainage inlets.
• Store fuel, paint, cleaners, and pesticides in sealed containers under cover.
• Report blocked, damaged, or overflowing catch basins to the City of Susanville.
• Use proper disposal services for chemicals, oil, and other household hazardous materials.

Keeping Local Waterways Clear

Stormwater maintenance works best when public agencies, businesses, and residents each prevent avoidable problems. Simple actions—such as keeping landscaping materials off the pavement and cleaning loose debris from a nearby grate—can reduce flooding risks and protect water quality.

Before the next storm, take a safe look at the drainage inlets near your property. Use the City of Susanville Public Works resources to locate information, report infrastructure concerns, and learn how to dispose of materials that should never enter the stormwater system.