Backwater Valves, Weeping Tile And Sump Pumps

Flood prevention devices like backwater valves and sump pumps can be valuable home drainage assets, but not everyone needs one. Consider your entire home drainage system, what type of home you have, where you live, method of servicing, and your flooding history before rushing out to buy and install these devices. 

Screen Shot 2019-04-08 at 1.55.29 PM

A backwater valve sits inside a home’s branch or main sanitary sewer line. Its job is to prevent sewage from returning up a sanitary sewer line and entering the basement. It is an effective last line of defence and is recommended for all homes that are at risk of flooding. 

There are two types of backwater valves. Both work well, but it is important to install the right one. The sanitary service line entering a home needs a vented backwater valve. Branch lines coming off the main line need a non-vented valve. You may need more than one valve depending on your home’s internal plumbing. A qualified plumber can test your system and recommend the correct installation. 

During a storm, sanitary wastewater trying to flow back into a home causes the backwater valve to close its flap. This action prevents sewage from re-entering the home, but it also means water from inside your home can’t get out until the valve reopens. 

Backwater valves need to be cleaned and maintained to work properly (Chapter 6). Also, older backwater valves have metal flaps (brass and cast iron). Cast iron flappers can corrode over time, which can cause them to stick. Once this occurs, they should be replaced with a valve that has a plastic flap. 


WScreen Shot 2019-04-08 at 1.52.15 PMeeping tile is a perforated plastic pipe that surrounds the foundation of a home. It sits in a bed of gravel, allowing excess groundwater to seep into it. This water is channelled to a sump pump, or the stormwater sewer system, depending on the age of the home. 

Remember: When the valve closes the sewer line, you should not use the toilet, sink, shower, washer, dishwasher, or anything else that discharges wastewater. The wastewater will have nowhere to go except up the floor drain and into your basement 

For development prior to 1988, weeping tile flows were directed to the sanitary sewer main and combined sewer main. As of 1988, new development is required to direct weeping tile to the foundation service where available. 

Installing or repairing weeping tile is expensive, but necessary in some cases. For example, weeping tile that is collapsed or clogged by debris should be repaired to prevent damage to the foundation and basement walls. You should seek professional advice from a plumber or qualified contractor before making any decisions. 


Screen Shot 2019-04-08 at 1.53.11 PMThe majority of homes built since 1988 have a sump pump. A working pump plays an important part in flood prevention, channelling groundwater out and away from the home. If your home was built after 1988, you should be aware of the condition of your pump and whether it needs replacing. A good quality pump should last around 10 years, depending on how often it is working and the acidity and dirtiness of the water. 

How do you find out whether or not you need to replace your pump? If you need to replace it, what should you look for in a new pump? 


Different manufacturers have different recommendations for testing and maintaining your pump. Some recommend running the pump every two to three months, while others recommend a yearly test. Follow any recommendations provided by the manufacturer. The pump should be located in a shallow pit or sump at the lowest point in your basement. Once you’ve located the pump, you can perform a simple three-step test to ensure the pump is working properly: 

Screen Shot 2019-04-08 at 1.53.51 PM1. Check to make sure power is running to the pump circuit. 

2. Pour enough water into the sump pit for the pump to begin working. 

3. Check the outside pipe to ensure that water is flowing from the discharge line outside your home. In some cases, the pump may seem to run but not pump water.

If you test the pump and it is not working properly: 

  1. Check for debris blocking the suction intake. 
  2. Listen for strange noises coming from the motor. 
  3. Check for oil in the sump well (may indicate a failed pump seal). 
  4. If the activating switch for the pump works on a float, check that the float is not restricted. 

Depending on the problems you encounter, you may want to consider getting your sump pump serviced or replaced. 

Screen Shot 2019-04-08 at 2.01.34 PMOTHER FACTORS 

Freezing: If you pump is operating during freezing weather, there is a risk of freezing and line blockage. It is best to disconnect outside hoses prior to winter. 

Recycling: If water from your sump hose discharges too close to your foundation, the water may recycle and end up back in your system, possibly endangering your foundation and wearing out your pump. 


There are some basic criteria for choosing a pump: size or capacity, pump type, and horsepower. There are other factors specific to your home that may also influence your choice of pump, such as the volume of water your drainage system has to handle or the amount of grit in the water. In the end, you have to balance your needs with how much you want to pay. You can buy a cheaper pump, but don’t expect it to perform as long or as well. A higher quality pump is built from top quality components. 

Horsepower (hp) 

  • Minimum 1/3 hp recommended. 


  • Make sure to size your pump properly to ensure greatest efficiency. 
  • Get information on the pump capacity (the amount of water pumped in gallons per minute) and the height and distance the water needs to travel (referred to as “head”). 
  • To avoid clogging, the pump should be able to pass stones of up to 10 millimetres through the pipes. 
  • Pumping head should be a minimum of approximately 10 feet. 
  • Discharge line should be 1 1/4 inch pipe. 

Common types: submersible, pedestal, and water-powered. 

  • Submersible is most common. 
  • Pedestal type may be better in highly corrosive areas. 
  • Water-powered pumps are not as efficient as electric. 
  • It is a good idea to

QUAScreen Shot 2019-04-08 at 2.01.43 PMLITY 

Pumps are tested against general standards and rated accordingly. Before purchasing a pump, check whether the pump meets CSA standards and displays a “CSA Approved” sticker. 


If your sump pit is incorrectly sized, it will affect the operation of the pump. The pump is most efficient when it is working at its optimal flow rate, based on the capacity of the pit. 

A sump pit cover is required, and should be child proof.