I am looking at houses and before I buy I want to sure that I understand the flood zone classifications.

The long term flood risk assessment for locations in England (website 1)

has 3 categories for flood warnings.

1. Flood risk from rivers or the sea
2. Flood risk from surface water
3. Flood risk from reservoirs

1. https://flood-warning-information.service.gov.uk/long-term-flood-risk

2. http://www.checkmyfloodrisk.co.uk/

Website 1 breaks these areas down into 4 flood risk categories:
High Risk: greater than once every 30 years

Medium risk: between once every 100 and 30 years

Low risk: between once every 1000 and 100 years

Very Low risk: less than once every 1000 years

It is obviously preferable to be in the very low risk area for categories A, B & C.

I have been looking at website 2 and it shows flood maps with different or slightly different areas to the maps on website 1. What is annoying is that on website 2 you can be in the very low risk area and then when you search for a house in that same area on website 1 it can show very low for category a) and c) flooding but it may be low or medium risk for surface water flooding.

I am aiming to buy a house somewhere with the category a) and c) flood risk to be very low.

My question is how bad is it to a buy a house in an area with low or medium risk of surface water flooding? Does anyone have any experience of this?

Does anyone know which flood risk zone the house would have to be in for the mortgage lender to not lend on the property?

Cheers

No answer but check on house insurance too as insurers are (understandably) increasing premiums on any properties at risk. In fact, some may refuse cover.

Well, my knowlege is a little out if date these days, but the first website is the .gov website with the “official” information – all Environment Agency info is now on .gov after the cull of all the individual Agency websites a few years ago. The second website claims to use EA data and only for rivers and the sea, but it isn’t clear how up to date that might be. If it was me, I wouldn’t put any faith in website 2 over website 1, as the data sets seem more limited and the data may be older.

On insurance, obviously it’s best to avoid flood risk areas but the insurance industry and government thrashed out the “flood Re” scheme a little while ago, to reduce the problem homeowners in flood risk areas had with rising premiums etc – Flood Re has its own website, which might be handy to look at.

On the sources of flooding, be careful you are comparing apples with apples. Surface water flood modelling is much newer than river and sea modelling and it is complex in terms of where water runs in major downpours. It is a useful indicator, but might not give you as much detail as the river and sea stuff – is your house at the bottom of a large hill? Guess where the water might end up in a massive storm… that kind of thing.

Reservoir breach, well it’ll be a big deal if it happens but that’s hard to attach a probability to, because it depends on maintenance and operation, as well as weather events.

Check the maps, but the formal searches during the buying process will also return this stuff, often through data suppliers like Envirocheck. Doesn’t guarantee anything though and understanding and accepting the probability / risk is part of the personal decision making – good luck!

Reservoirs are also subject to a very strict legislated inspection regime.  The face of a dam has to be inspected weekly.

Having said that, we had a couple of slips of dams in recent bad weather in the west midlands, so it’s not impossible for a reservoir to be compromised unexpectedly.   They normally go with a fair degree of warning however, as reservoir failure is basically not considered to be acceptable.

Buy one at the top of a hill.

Ask yourself, do I believe in climate change?

Then ask yourself do I believe climate change will result in weather events where records may be set?

Then ask yourself do I want that house with that risk?

You might decide to buy it, just manage the risk

I wouldn’t touch anything with a bargepole that has a chance of flooding personally. It really just isn’t worth it.

I work in in Flood Risk Management in Scotland where we have slightly differant mapping. However I grew up in Hexham, Northumberland.

Looking at the 2 websites, from my personal experience of growing up in Hexham, the flood maps on the first website look more accurate.

Personally, I wouldn’t buy a property at any risk of flooding from rivers or the sea. Surface water is slightly differant as the modelling doesn’t take into account drainage etc but you are at the mercy of local councils and water companies to maintain their drainage networks on that one.

As mentioned above Climate Change is predicted to increase extreme weather events in this country, the modelling that is carried out to include this adds an 20% to volume of water predicted for a given event.

Also consider how hard it will be to sell a property that is at flood risk, my parents old house was in a coastal and fluvial flood zone and despite having only one recorded flood on record they really struggled to sell, eventually selling to a local who knew the flood history and was willing to ignore the risk on the maps.

All that said, what the maps dont tell you is depth of flooding, they will show anything from 0.1m upwards and there are various property level protection (PLP) products on the market such as flood gates, airbrick caps etc which will help in the event of a small flood.

Personally I wouldn’t touch a house in flood zone 3 with a barge pole, but that’s after seeing the effects of flooding first hand on numerous occasions.

As above, check out the EA flood map for planning on GOV.UK, this will have the most up to date flood maps on. Other things to bear in mind are whether the property has flooded previously (worth checking out historic flooding), whether or not it’s defended (and the nature of those defences – i.e. hard engineered defence, with little risk of failure, is it defended by a pumped system etc.) which will give you an idea of probability of flooding versus impacts.

The surface water flood map shouldn’t really be used at individual property level, so shouldn’t be a factor in insurance, it will give you an indication of whether the area is at risk of surface water flooding though. Things to look out for are: is the property higher than the road/pavement out front; does the road have a drainage system; are there fields out the back that slope down towards the property all things that could impact whether or not a property is likley to be affected by surface water flooding.

I can’t really add anything on reservoirs over and above what’s already been said.

As above – avoid, its only going to get worse.

I moved in 2015 because in 2011 that first website said I was in a low risk area & the edge of the high risk area was 197m from my door.

December 2012 people 160m from my place towards the high risk area were advised to leave home after heavy rainfall.

2013 the EA revised the risk areas – my place was now in the medium risk area with the edge of the high risk area 16m from my door!

I now live less than a mile away but 44ft higher & much happier.

I live in Carlisle, home to a couple of the biggest floods in uk history.  On both occasions I woke the next day completely oblivious to the floods.  In fact I tried to drive across town on the first occasion only to find my journey blocked after 1ml by a gradual sea of water.  It was something out of a end of world programme.

It pays to have a wife who has worked in a solicitors conveyancing dept for 20yrs+ when considering where to buy your next house.

After the experiences we have seen I would put a lot of onus on the councils ability to maintain drains, not build new estates at the bottom of known flooding areas and basically avoid anywhere borderline.  Our councils/governments have spent many many millions locally on flood defences.  Guess what happened when the second floods hit?  The water couldn’t get over the flood defences but instead moved a little further down the line and burst the banks there.  Same result 🙁

Buy near top of hill +1

If you contact the EA and request some flood information for the house you are looking at they can give you a map with the flood zones on. You can also request the estimated flood depths (I think it’s called product 4) which might be useful.

Climate Change is predicted to increase extreme weather events in this country, the modelling that is carried out to include this adds an 20% to volume of water predicted for a given event.

The 20% has been revised now and is more catchment specific, in some places it is still 20% but in others it is up to a 70% increase so might be worth taking into account.

As others have said I would avoid buying a house in a fluvial flood zone if possible, it would only take a couple of days of rain and you’ll be sorting it out for months afterwards…

We’re in a house with no risk of flooding from rivers or sea, but risk of surface water flooding.  I’m happy with the risk, the plot is on a slope and water reaching the house would flow round it without threatening the damp proof course.

No issues from mortgage co that I’m aware of.  Home insurance is with pedalcover, Darren reckons my insurance is a bit pricier because of it.  I’d be quite happy to take the flood cover off, but it doesn’t seem to be an option.

top of hill no guarantee …. i live at 85m a top a hill … my neighbour up above me floods reasonably regularly in the heavy rains thanks to my neighbours below me not keeping their ditches clear – ive come close to my garage flooding in the past. – at least my house is another 4ft above that.

dont just assume your atop a hill your safe.

also flood defences work both ways….. they keep river water out and if the drains cant cope it keeps surface water in….. witnessed biblical rain 3 weeks ago in ballater and the river was so low you could have walked across it in flipflops and barely got wet feet ….. the highstreet however was knee deep and the shops were flooding…..

I wouldn’t touch anything with a bargepole that has a chance of flooding personally. It really just isn’t worth it.

This, +1000%.  It may have no recorded history of flooding but then it may not have been there very long.  But when it floods, and it will one day, you’ll never be able to sell it.

As above, avoid. Mortagage will be fine but insurance either v expensive or not possible unless via flood re but that is only for the next 20 yrs or something, it won’t continue forever. Also you may know this already but 1 in 100 years does not mean what it sounds like it should. Terminology is something we are not good at in science and this is a prime example,   I think there is in general a mid understanding of what this means…..1% chance every/any year not oh it happened last year so that’s it done for another 99 years.

I wouldn’t touch anything with a bargepole that has a chance of flooding personally. It really just isn’t worth it

Go and look at it. make a judgement. flood risk is modelled. models are always wrong, sometimes useful.  Surface water flood modelling especially.  There may be obvious things about the lay of the land that make you realise if certain things happened, the water would definitely go away from the house. Or towards it.

You might not be able to convince your insurers to take off the high risk premium load on the basis of your analysis, but that doesn’t mean the model is right, that nature will defy physics, water will flow uphill and flood your house rendering it worthless.

You might also visit and wonder why it’s not underwater already.

Okay guys cheers for the advice.

This is what the industry (construction, geotechnical, hydrogeological, insurance and loss adjusters) usually turn to:

http://www.envirocheck.co.uk/report/flood-screening-report

Get a good map of the area, 1:25k or 1:10k, look at the contours and nearest watercourses, those should give a bit of a clue.

Live across the road from a flood plain. River over there that sometimes floods and at worst it spills onto the road but never gets to the houses on the other side.

It never came up on the survey and obviously estate agent weren’t going to tell me. The only issue has been with insurance as a lot just go by the postcode or flood risk maps but not history. Many won’t touch my place now but a few will and not particularly more expensive.

Type of flooding here isn’t at risk from sea level rise. Maybe increasing wet weather, though to be honest I’ve seen it flood less in recent years despite wetter winters. Not a hint of flood this year.

The number of houses up for sale, sold and then up for sale again though makes me wonder if people back out on the survey. Or just sales fall through due to chain issues or they can’t get a mortgage for financial reasons.

As Count Zero suggested, get an OS map and check for water courses. Then look at contour lines and buy a house at least 10m above the nearest and biggest.

The flood events are done on probability by people who deal in numbers. You have to live there in real life. A once in 50 year flood may happen 50 years from any point in that 50 years (or it may not happen at all because its a probability not a certainty). So that could be within 99 years 364 day to every year (until it is then re classified using the new frequency). (as slowmogirl alluded to)

Also check you can get house insurance*.

*Edit – others have covered this

Like @tomcrow99 this is my area of work.

I’d echo the advice not to buy in any form of floodplain if you can help it – i’ve helped clear out a flooded property and the devastation it does to personal possessions, memories and the fabric of the building can be really emotional for those that suffer it. Its also a b****r to have to deal with being in temporary accommodation for 12 months whilst the refurb is being done, and then trying to get insurance and ultimately sell it on if someone else is prepared to take the same risk (which in reality will be a higher risk as it’ll be in the future, climate change…)

Phone/write an email to your local EA office and ask for further information on the property, any detailed model results they may have and any flood history.

There’s nothing legally binding the insurance, lending or house sales industry to using the government funded and produced data, they can supplement with their own, or ignore it all and just work on a postcode and history. Unfortunately you won’t get to see some of it until after you’ve started conveyancing though. I saw some recently from a friend who was buying a property and it was complete gibberish – the source of flooding they were referring to simply couldn’t exist in that particular location.

If its not flooded that doesn’t mean it won’t.

If you’re prepared to take the risk now then someone you sell it to might not be in the future when the risk will be worse.

If its only surface water flooding then this tends to be modelled poorly, so if its immediately near a surface water zone then i’d still avoid.

If its on a hill it can still flood from surface water runoff caused by poor land management.

I think what tomd1984 is saying is don’t buy a house period.