High Risk Surface Water Flooding on House Purchase

[Samara26]

I'm in the process of buying a house and I have checked the Gov.Uk flood risk, which turns out to be a high risk for surface water flooding.

Is this something I need to worry about? I wasn't told by either the estate agency or the owners who did 2 viewings with me and built the house.

What should I do?

I've been looking for a house for a year and now all the rates have gone up so I'd have to buy in a cheaper area or a smaller house- either way I'd lose a lot of money.

Most of the advice here, including from someone who worked in the Environment Agency, say to walk away.
www.mumsnet.com/talk/am_i_being_unreasonable/4587458-found-out-devastating-news-about-house-we-are-about-to-buy-should-we-pull-out

There are problems with this but 3m homes have the risk. See the attached speech and decide if the property is worth the risk. Where is it ? The article gives en idea as to the areas most likely to flood. I might well give up on this property but where it is would inform the decision and work being undertaken to improve the situation.

I'd walk away. Water is the most damaging element on a property and flooding is likely to get worse over the next 50 years as the world gets hotter.. not just from rivers and seas but surface water too because as the ground hardens in the heat water doesn't run away as efficiently.
BUT... if you are tempted to proceed, ring your current buildings insurance company and ask for a quote. Houses in flood risk areas are often more expensive to insure.

I recently moved and flood risk was one of my top risk factors that would rule a place out.

It's in Maidstone. I can't believe estate agebts an owners aren't obligated to be upfront about this as soon as u express an interest in buying a property? It feels m like misrepresentation

I can't believe estate agebts an owners aren't obligated to be upfront about this as soon as u express an interest in buying a property? It feels m like misrepresentation

Our estate agent didn't even know the house we were buying had previously flooded. We found out very late on in the process and the vendors were very evasive and wouldn't provide any info/evidence. We ended up feeling pushed into proceeding and have since found out from a neighbour that the 'little bit of water' that got in was absolute bullshit - it was properly flooded.

I would never buy a house in a flood plain or risk of flooding. You may not be able to get it insured against flooding. If you can get it insured the premium will be astronomical. Look for something else.

There's different kinds of flooding though... Surface water flooding is a risk for a lot of houses in London area for example. But they all sell just fine.
If there's no river or stream nearby then it may be that SUDS will be enough (soakaways, permeable patios etc). It also depends on what's around - are you downhill from a largely cemented estate, this sort of thing.

If you are that far ahead... then wait for your searches to come through, ask your lawyers opinion, search news reports, talk to neighbours and check the insurance premium.

Flooding events are goong to happen regularly - due to climate change the kinds of flood that were previously considered 'once in a lifetime" frequently will happen every 3-5 years.

Lots of houses have been built on flood plains. Don't buy one unless it is either already adapted for regular flooding or the price reflects the cost of installing such adaptions immediately after purchase.

Appropriate adaptations - a layout with no water-permeable materials on the ground floor - eg floors are not wood or carpet but tiles or poured concrete. All plug sockets on ground floor at least a metre from the ground. Houses where the dround floor is just a garage, utility room and WC, with kitchen and living room on the first floor and bedrooms on the second floor are fine. Outer doors can hae a flood barrier fitted which protects against floods of up to knee height and you can step over from the flooded oitsude into the dry interior. You need air bricks but floodproof airbricks xan be used which seal off when water levels rise.

Huge areas of London are in high risk areas but the houses are perfectly insurable. The government has a scheme called Flood RE that helps owners find suitable insurance.

I wouldn’t walk away, but I would ask if
any of the local areas have been flooded recently, and ask the owners careful questions about flooding in their memory.

The flat I previously lived in comes up as high surface water flood risk. I only found out when searching for my new property and out of interest. I lived in that flat for 7 years and in the area my whole life and never knew that road to flood. During the storms in 2020 Ciara etc the garden became quite boggy but I never felt the house was at risk. There was also a step up to the house front and back which meant water would have to be pretty high to come into the house.

I work for environment agency, in flood response! Last house we had had surface water risk, we took our chances (it was on a hill near some moors). Heavy downpour and waterlogged fields lead to some flooding on our street. Water path did exactly what map said and flowed down side of our house, but neighbours took a direct hit. Thankfully with the help of a whole street of neighbours and me advising, we managed to keep it out of their house. Both our houses had extra drainage along front to help flow water in wet weather.

there is so much surface water risk everywhere that it’s going to be hard to escape it. It’s also a hard thing to map (basically done looking at contours) and certainly unpredictable, so you won’t get any warning other than weather forecast. It all depends on where it is. London basement flat avoid entirely. heavily urbanised area and house in a dip at bottom of a hill, also avoid.

If you love it and it’s not in any of these areas, I’d take a chance. The good thing with surface water flooding is that it doesn’t hang around long, so if you have good drainage and can put out something to deflect the flow you might get away with it.

Agree with katkincake my house also supposed to be at surface water risk. It has never flooded, including in last 3 years I lived here when it rained heavily. We are two thirds way up a hill, but with a wide road area above us. Looking at the contours in reality flash flooding would be likely to be channelled past us. I will look at having something in place to block doors and valves on drains in house when I get the chance, but it does seem like a remote risk.

Forgot to add earlier. River and coastal flooding a whole other ball game so I would give different advice then!

Also disclaimer, don’t take this as official EA advice - just a fellow Mumsnetter trying to help with decision making on such a big purchase (we’re also in process of buying) 😁

Where did the high flood risk came up? We’re buying a house and the environmental agency maps showed surface flood risk as medium (essentially the road outside the house might be a route for water coming downhill), but the proper environmental search we paid for came back as negligible risk! It’s hard to know which is more accurate but we’re going ahead as we felt the searches we’ve done should be more accurate

Just re-read your post. So is it worth you paying for the proper environmental risk searches (ours were done by Groundsure) and seeing what the risk comes up as?

@Samara26

I would drill down into floods in Maidstone from surface water. Why is it high risk? This is the drains being overwhelmed. It can mean the water comes back up into the house. It’s more likely in built up areas as the article I posted says. Farmland and grass areas do soak up water. Concreted front lawns don’t. Some areas do have good schemes in place. So try and get more info on the precise area.

I see this as something searches should go. Estate agents don’t do searches. You can also get some info yourself. These risks cover big areas. I assume other houses have sold in Maidstone? So is anyone else worried?

An estate agent friend told me of a house he had sold once that came up as 'high risk of flooding from river' on the survey which would have meant astronomical insurance for any buyer - turns out that the survey was done on maps (rather than a visit) which did indeed show the property only 500metres from the river which flooded regularly. Unfortunately the person interpreting the map on their computer couldn't read contour lines and missed the fact that whilst the property was 500m from the river it was also several hundred meters higher than the river up the hill! Survey was re-done by someone more experienced and buyer never had any issues with flooding from the river

My house comes up as high risk for surface flooding on the EA search but when we did the actual environmental searches the risk was only moderate. Not sure which one is more believable but we went ahead with it anyway. The property is at the top of a hill but with a large road right above us. I've been told that increases the risk in the EA calculations but not sure if that's true. Anyway, we have drainage on our patio and have had absolutely no issue getting insured. Our insurance costs £300 a year (building and contents) but only because it's a 200 year old non-standard construction. Otherwise it would have been below £100.

Has it flooded in the last 50 years?
I'm in London and my report came back with risk of flooding, partly naciste I live within 500m of a stream (which has very high rock sides), partly due to surface flooding.
I weighed it up and realised huge areas of London would come under this level of risk. There has been no history of actual flooding either. So I went ahead.

Our property lies within an area of where the EA maps show patches of moderate to high risk of surface water flooding. The environmental survey for the property shows no surface water flood risk.

I’d pay for an environmental report if you haven’t already done so.

I also checked out the local borehole data, which indicated any surface water issues would likely be on recently built roadways and should be handled by the sw drainage in place.

This report from Kent CC might be useful re Maidstone. I found it in draft form but more searching might find the final version. It’s useful.

I would look at the local terrain carefully and examine the maps. I've just looked up the flood risk for my property and SEPA (it's in Scotland so equivalent of the EA) have it as a medium risk for surface water flooding along with other areas of the estate, which is a 10% chance of flooding every year. I've been here 15 years and never seen more than a puddle around one of the grids where the block paving has subsided slightly. And we've had some very intense rain in that time! Some of the areas marked as high risk on their maps do flood but only in very localised areas and usually due to blocked road gullies. I would look at the lie of the land in more detail and assess if you think it's a real risk......just think that water naturally flows down hill!

Are you sure it's 10% Emma? My house is shown as medium surface water flooding risk by sepa which it says is 0.5% chance of flooding which I decided was a risk worth taking.

sorry, yes medium is 0.5% and high is 10%. I'm not convinced how accurate it is though as there's roads locally that flood without fail every year and they aren't shown as at risk at all! I wonder if it's based purely on ground topography and doesn't factor in local features such as walls and manmade embankments.