Sewer Backup prevention & reporting

Emergency Information

If you experience a sewer backup, call us at the numbers listed below.

We will dispatch a maintenance crew to your address to determine if the stoppage is in the City sewer main or the private sewer lateral.  If the City main is found to be clear, it is the responsibility of the property owner to call a plumber or sewer/drain cleaning service to correct the problem. The property owner is responsible for maintaining adequate flow to and through the sewer lateral from the property structure to and into the City sewer main.  If the blockage is in the City main we will fix it as quickly as possible and keep you informed about what is being done.

    Sanitary Sewer Emergency Numbers: Link to "Coping with Sanitary Sewer Backups"

    During normal business hours (8:30am - 5:00pm, Mon-Fri)  (608) 789-7536

    After 5:00pm on weekdays, weekends, or on holidays           (608) 789-7330



When waste not intended to be placed in the sanitary sewer like diapers, napkins, grease, paper towels or other non dispersable items get stuck on their way from your toilet, sink or bathtub to the sewer, disgusting back-ups may occur. These clogs can happen in the pipes inside your home or in the lateral line leading from your home. If plugged, this will not allow the waste water to flow to the municipal sewer system and may "back up" into the property. Clogs in the lateral may also be caused by tree roots penetrating the pipe and restricting flow.

The following are all reasons a sanitary sewer backup in your sewer drains may occur. For more detailed explanations of materials that clog the sanitary sewer service laterals and mains, visit the What NOT to Flush page.


Grease bonds to the sanitary sewer pipe, which can restrict and ultimately cut off the private sanitary sewer service from the municipal waste water system.

Solution: Do not pour grease or other illegal substances down the drain, as they will eventually clog the sanitary sewer service lines.


If the sanitary sewer service pipe is too small, or is partially clogged, the waste leaving the house from toilets, bathtubs, laundry rooms and dishwashers will back up into the house. This backup can usually be seen in the basement bathroom or laundry room.

Solution: Ensure you are only flushing acceptable human body waste, toilet paper and dirty water.


Shrubs and trees, seeking moisture, will make their way into sewer line cracks.  These roots can cause extensive damage.  They may start out small, getting into a small crack in the pipe; but as the tree or shrub continues to grow, so does the root.  After time, this causes your sewer line to break, which in turn allows debris to hang up in the line, thus causing a back up. 

Solution: One way to prevent roots from entering your line is to replace your line and tap with new plastic pipe.   The other alternative is to be careful about planting greenery around your sewer line or you may purchase a product containing "copper sulfate", which helps to kill roots when you pour it down your drain each year.   This product should be used with extreme caution.  If you have continuing problems with tree roots in your lateral, you may have to have them cut periodically by having the lateral rodded.


When the ground around the sanitary sewer service is saturated (after a heavy rain or in an area with ponding water), the rainwater can seep into the cracks in the pipe.

Solution: Replace the cracked sanitary sewer service.


Property owners can install a drain line check valve to prevent backups. For an existing building, the estimated cost is $1000. Most of the expense is for labor to remove a section of the basement floor, uncover the drain, install the check valve, and then repair the basement floor.

The check valve is not fool proof, and there are some circumstances where it may fail to prevent a backup. Still, it will eliminate many of the problems. A plumbing permit is required for the installation.


It is important to understand that the City of La Crosse Sanitary Sewer Utility will not pay for damages caused by sewer backups. If it the property owner feels the problem was caused by negligence on behalf of the utility, they would have to follow the City of La Crosse Liability Claims process.

Many homeowners' insurance policies exclude damage resulting from sewer backups, thus creating a financial hardship to the property owner in the event of an incident. However, some insurance companies do provide sewer backup coverage with a special rider.  If you are concerned about the possibility of a sewer backup and want to insure that you are covered, the utility urges you to check with your home or property insurer regarding the availability of sewer backup insurance.


Another concern that property owners have is that they can smell sewer odors inside their house or building.  There are many ways to prevent this from occurring.  Under each drain in your plumbing system, there is a "P-Trap".  If there is water in this fitting, odors or gasses from the sewer cannot enter through the drain from either the property owner's lateral or the City main. “P-Traps” will dry out faster in the wintertime when the humidity is low.  Periodically check to make sure that unused floor drains, sinks etc. have water in the "P-trap".  Another way to prevent sewer odor is to ensure that the vents, which are located on your roof, are free from bird nests, leaves, etc.  When these vents are clear, the sewer odors will escape through these vents.


Sanitary sewer basement backups can be caused by a variety of factors. Often times,basement backups occur during heavy rain storms. This is due to the fact that the sanitary sewer systems are inundated by an overabundance of rain, or "grey" water. In La Crosse, the sanitary sewer system is separate from the storm sewer system.  This means rain water is entering the system through either inflow (direct connection to the sanitary system), or infiltration (water entering the system through an indirect source).


  • Roof Drain Connection
  • Uncapped cleanout
  • Storm sewer Cross-connection
  • Illegal foundation drain connection


  • Root intrusion into lateral
  • Cracked or broken laterals/mains
  • Defective manholes
  • Defective lateral connections

If the property having issues with backups during rain event have a sump pump, the sump pump may be overloaded. A backup may also occur if the power goes out during a heavy rain event. The sump pump system is designed to keep groundwater out of the basement, but can also act as a conduit to bring water in.

Storm water sump pumps are basement pumps, which remove water that collects below a basement slab floor and pump it to an outlet in the yard. These pumps are normally electrically given. Therefore, the pumps will not function during a power outage. If the power outage occurs during a rainstorm, water that collects in the footing drains of the residence cannot be pumped out


There are several measures a property owner can take on their own to reduce the risk of basement backups.


One of the simplest things you can do to help keep water out of your basement is to make sure the dirt next to your home is properly graded, meaning it is pitched, or sloped away from the house.


Seal cracks in concrete next to your house, such as where a sidewalk meets your building, with something like a polyurethane sealant. Doing so can help keep water out of your basement.


Make sure the downspouts on your home or building are extended at least six to ten feet away from your basement. Every downspout can deliver up to 12 gallons of water a minute during a heavy storm, water you do not want causing damage to your basement. Be sure the downspouts are not connected to the footing drain, which collects water around the foundation along the basement walls. The sump pump typically pumps the water collected in the footing drain to the rear yard, often with a connection to a rear yard storm sewer.


You can install a larger sump pump, or geta backup system for your sump pump. When you lose power at home, your sump pump becomes useless, unless you have a backup system. Battery backup systems can buy enough time to get a generator running, or to borrow a generator for longer periods without power. Make sure the discharge pipe from your sump pump is at least six to ten feet away from your house.

Illegal Connection

If the storm water sump is connected to the private sanitary sewer rather than discharging water from the footing drains to the yard, the sanitary sewer can fill up with storm water. The sanitary sewer was

not sized to handle the additional flow from the footing drains. Therefore, sanitary backups in homes and manholes may result.



Other examples of illegal connections to sanitary sewer include:

  • Downspouts
  • Patio Drains
  • Rear Yard Drains
  • Removing covers off sanitary sewer manholes