80 Basement flooding – where is the responsibility?

Last week (20-26 November) was Flood Action Week in the UK.? The aim of the week was to get the general public to understand their flood risk and take action to reduce it.

There were messages from the Environment Agency, the government, professional bodies, pressure groups and others; but I wonder how many of the general public were aware of it and did take any action.

CIWEM (the Chartered Institution of Water and Environmental Management) quoted recent polling suggesting that nearly two in three households that are at risk from flooding do not believe their homes could flood, primarily because they have not experienced flooding in the past.? But the fact that it hasn’t flooded while you have been living there doesn’t mean that it never has and with urban growth and climate change it certainly doesn’t mean that it won’t in the future.

In England there are over 5 million properties at risk of flooding with 3.4 million of those at risk from local surface water or sewer flooding rather than large scale river or coastal flooding.

Estimates give the average damage cost of a flooded home as about ￡30,000.? But it also has significant mental health impacts that can last for 2 years or more. ?Depression, anxiety and PTSD affect up to a third of people who have been flooded.

If you are flooded, the physical damage should be paid for by your insurance policy (if you have one) but the mental health impacts are paid for by the NHS (if you can get an appointment) and by society and the economy.

There is evidence that making your home flood resistant or flood resilient can significantly reduce the damage cost and probably also reduces the mental health impact.

I want to focus in particular on flooding of basement properties, which is a significant problem in older cities including London.? These are not only more likely to flood as they are below ground level and potentially below the level of the drainage systems, but they can also have even more impact with a potential risk to life.

The Environment Agency and the Government are urging people to make changes to their property to protect themselves from flooding.? For basements this includes fitting non-return valves to stop flood water entering your property through the drains.? But is there anything in place to support this plea, or does it just put all of the onus on the householder.

Who is responsible?

The current responsibility for measures to reduce the impact of basement flooding are confused with different approaches from different organisations and in different parts of the country.? I have titled this as the situation in England as I have not checked how it differs in other parts of the UK.? So which organisations are involved?

• Local authorities grant planning permission and building regulations approval for all development including basements.
• Water and Sewerage Companies have a duty to “effectually drain” properties in their area.
• Insurance companies have to pay out for repairing the damage to flooded properties that they have insured.
• Flood Re (a joint initiative between the government and the insurance sector) has the aim of making flood insurance more affordable.

New basements

Construction of a property with a basement, or a new basement to an existing property or conversion of an existing basement to a habitable space will require planning and building regulations approval.? Since 2002 Building Regulations have required a flood risk assessment to be carried out before new build or conversion and the householder is responsible for flood protection measures.

Local authorities set out their requirements in planning policy and these differ from authority to authority even with one city.

• “Fitting basements with a positive pumped device (or equivalent reflecting technological advances) will ensure that they are protected from sewer flooding. Fitting only a ‘non return valve’ is not acceptable as this is not effective in directing the flow of sewage away from the building.”
• “In addition, basements should have adequate mitigation measures such as non-return values or pumped sewage devices to prevent back-flows from the system during sewer flooding.”

Sewerage undertakers also give guidance on requirements for flood protection for new connections from basements.? These range from the patronising to the detailed.? Two examples are:

• “If your proposal includes basements or semi-basements don’t forget to consider protection against backflow.”
• “The following two options are set out within Part H1 of the Building Regulations 2010:

1. Where there is a high risk of internal flooding and known instances of surcharging sewers, the drainage from the basement should be pumped to ground floor level before discharging to the public sewer via a gravity connection.
2. Where there is a lower risk of internal flooding or pumping the flows to the ground floor level is not a viable option, then a non-return valve should be installed on the drainage system from the basement prior to the connection to the public sewerage network.”

(To be pedantic, I think that the word “risk” in those options should be “probability”.)

In all cases of development or conversion since 2002 the householder is responsible for installing and maintaining flood protection for basements.

Existing basements

For basements built or converted before 2002 the situation is less clear cut.? The sewerage undertaker has a duty to “effectively drain” properties and their curtilages.? However the definition of “effectively drain” is rather vague.? The Water Industry Act does give a right to connect a drain to the public sewer, but it doesn’t specify that it must be a gravity connection that flows downhill.? There may be case law that clarifies this that I haven’t found, but it is generally assumed that the sewerage undertaker has to drain basements that have an existing connection to the sewerage system.

A sewerage undertaker will generally only take action if you have already been flooded at least once and will then consider a protection device for the individual property.? As an example Thames Water has already installed thousands of individual property pumps although they would now aim to use a simple non-return valve whenever possible.? The protection device would be the responsibility of the sewerage undertaker.? The devices are likely to be within the curtilage or even within the property, so it is difficult for sewerage undertakers to take that responsibility.? It would be better if it lay with the householder, as under current building regulations.

Even after you have been flooded an insurance company would not automatically pay for a protection device to prevent future flooding.? The website of the Association of British Insurers states that this would be an improvement to the property and so would have to be paid for by the householder.

However, Flood Re has a “Build Back Better” initiative that enables homeowners to install property flood resilience measures up to the value of ￡10?000 when repairing their properties after a flood.? Future maintenance of any measures installed would then be the responsibility of the householder.

It seems that no organisation will pay for property level protection to reduce the risk before you have been flooded.? So the insurer needs to pay out and you need to suffer mental health impact before it is seen to be worth doing anything.

Other countries

In Canada where drainage and sewerage is the responsibility of the municipalities, many cities have a proactive approach of providing grants to householder with basements to subsidise the cost of flood prevention measures.? These do not seem to rely on having previously been flooded but are based on assessment of risk.? Grants are typically up to C$3?000.? There are generally requirements for the work to be done by qualified staff or by approved contractors.?

What should change

At present we have a two tier system that depends on when the basement was built or converted.? If after 2002 then it is the householder’s responsibility to provide flood protection.? If before then, the sewerage undertaker is responsible.? This situation is neither practical nor equitable.?

So could we through a combination of regulation and incentives encourage householders to fit and maintain flood protection for older basements even if they haven’t yet flooded??

There would be savings to the insurance companies and to the national economy from preventing flooding so there could be a subsidy from a body such as Flood Re.

Recent research by Wavin found that 71% of house buyers were concerned about flood risk.? There are already regulations requiring a certificate to show that the electrical system is safe before letting or selling a property.? Extending this to flood safety would mean that gradually the housing stock would be improved as it changed hands.? We would need an agreed interpretation of the building regulations as to when a non-return valve is acceptable and when a pumped discharge is required.

Some people have argued that we should not encourage householders to fit basement flood protection as this could cause a slight increase in flood risk for other, unprotected properties.? This would be akin to banning burglar alarms as they divert burglars to the unprotected house next door.? Organisations proposing either policy would surely face legal challenge and reputational damage.