We have to be frank about sewer backup and basement flooding

1 March 24, 2014 at 2:24 pm by

If we as an industry are to have any shot at all of reducing the impact of sewer backup and basement flooding, we have to start cutting through the myths, misinformation, exaggeration, conventional wisdom and everything else that is getting in the way of our addressing the problem of sewer backup/basement flooding and moving on with implementing solutions. Just a few of the wrongheaded comments often heard include…

“We are getting more sewer backup/basement flood claims these days because more people are finishing their basements.”

This old pearl comes up time and time again when speaking of the sewer backup/basement flooding problem and while there may be some truth to it, the fact of the matter is that Canadians have been finishing their basements for decades (I’m pushing 50 and, as a boy, my basement was finished). The real truth here is not that we are finishing our basements, it’s HOW we now finish basements. Gone are the days of walnut panelling, shag carpeting and peel and stick floor tiles. We now live in an era where basements are appointed as nicely (or, sometimes, nicer) than the rest of the house: drywalled walls, drywalled ceilings, pot lights, hardwood or laminate floors, fine carpets etc. After this work is done, rather than send down the castaway furniture from the upstairs living room, homeowners put brand new furniture downstairs, along with high efficiency furnaces, upgraded electrical service panels, flat panel TVs and so on. Mould remediation also often adds a good chunk of money to a sewer backup/basement flood claim.

“Basement flood claims are up because of home entertainment systems and computers.”

Perhaps there was some truth to this a few years ago, but the prices of both big screen televisions and computers have come way down. Again, it is largely the building products we choose and not the toys that are causing the bulk of the insured damage.

“Sewer backup/basement flooding only happens in old neighbourhoods in older parts of cities.”

Right now, the evidence seems to indicate that we get basement flooding where it rains hardest. There doesn’t appear to be much correlation between sewer backup/basement flooding and how old a home is, how old a neighbourhood or subdivision is, or whether the sewer system is combined or separated. Newer homes with separated sewer systems can and do experience sewer backup/basement flooding and concentrating only on older homes/neighbourhoods may leave an insurer exposed. Further, there is no correlation between vintage of home or subdivision or vintage and type of sewer system and FSA (postal code Forward Sortation Area). A subdivision or neighbourhood on one side of a street may be entirely different than one right across the road (one may be significantly older than the other, or the weeping tiles may be connected into the storm sewer on one side and into the sanitary on the other). Insurers need to be careful about using FSAs to delineate sewer backup/basement flood risk zones.

“Experiencing sewer backup/basement flooding must mean that the municipal sewer ‘broke’ or wasn’t working properly.”

Engineering investigations after sewer backup/basement flooding events often indicate that the sewer system performed exactly as designed and that it did not fail. The problem usually rests with the fact that the return period of the storm exceeded the design standard of the sewer system. Even new sewer systems aren’t designed to handle really exceptional storms. To put in a sewer system to handle an August 19, 2005 or July 8, 2013 Toronto storm event would require a phenomenal amount of money and the disruption from construction would be unparalleled. What’s more, even if such a sewer system was installed a homeowner may still experience sewer backup/basement flooding due to problems at the lot-level. The long and short of it is that blaming infrastructure for sewer backup/basement flooding may obscure the real cause of the surcharge or flooding, leading to incorrect courses of action that may give a false sense of security to both the homeowner and the insurer.

“Put in a backwater valve and all will be well.”

Backwater valves are very effective against sanitary surcharge into a basement, but they aren’t the ‘be all and end all.’ Depending on certain factors, installing a backwater valve without severing the home’s foundation drains and connecting them to a sump may actually cause a basement flood rather than prevent it. Yet some insurers are now automatically requesting or demanding a backwater valve be installed in an insured’s home under threat of cancelling sewer backup coverage. Insurers need to understand how backwater valves work, when they are helpful and when they can be harmful, and how the connection of a home’s foundation drains (i.e. whether to the storm or the sanitary) matters vis-à-vis causing self-flooding in a home. Backwater valves often work, but they aren’t a panacea.

“Backwater valves can cause flooding in a neighbour’s home.”

Conventional wisdom maintains that while installing a backwater valve may protect a home from sanitary surcharge, it may cause flooding in a neighbour’s home. While this could be the case, there currently isn’t any evidence definitively linking the two and any evidence gleaned to-date appears to be solely anecdotal. Oftentimes, the story is that a homeowner had never before experienced sewer backup until a neighbour put in a backwater valve. However, the causes of sewer backup/basement flooding are often so complex, that it would be very difficult to pin the cause of a basement flood on the installation of a backwater valve in a neighbour’s home. What’s more, groups like ICLR never suggest that only a backwater valve should be considered when attempting to reduce the risk of sewer backup/basement flooding. Other measures include taking actions to reduce the amount of storm water that enters a system in the first place (by disconnecting downspouts and foundation drains). Anecdotal evidence that backwater valves can cause flooding in other homes should not be a barrier to installing a backwater valve. With every hazard type and hazard event comes myths, mistruths, exaggerations and the like. With the heavily technical and complicated nature of sewer backup/basement flooding, the myths and mistruths will just be all the more. However with water damage claims being epidemic in Canada, we can never even hope to address the real issues and put solutions into place if our collective heads are in the wrong place. Hopefully this piece will set some people straight, and get us pointed in the direction we need to go so we can get water damage claims trends heading in the same direction as fire claims – down.

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1 Comment » for We have to be frank about sewer backup and basement flooding
  1. Jean Francis says:

    Factors I have noticed in sewer backup and basement flooding seem to: 1, extremely heavy rain showers which tend to inundate the properties drainage system. Agreeing with you that if possible to reduce the amount of storm water passing through a properties drainage. 2, the increase of hygiene products namely so called flushable wipes and also female hygiene products been flushed down the toilet. I never recommend any of these products are flush away. Often these products get jammed up in a back water valve! Causing backup.

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