To buy a house on a flood plain?

[Arkbuilder]

We have fallen in love with a house, offer accepted etc. Turns out it's the highest level of flood risk (3). There is a small brook that runs along one boundary. The owners had said it has flooded but never got to the house. We intended to build something bigger on the land. Is this a show stopper? Am I being a fool to proceed?

If you can afford massive landworks to improve drainage or can set aside flood storage land, I'd think about it if you really love it. Otherwise no.
An EA person told me once to never live on River Road, Brookside or anything else with water in the street name as an indicator of flood risk!

I’m not sure it’s shoe stopper but it would be a deal breaker.

I’d be looking for a new house

Can you clarify OP, you say you have fallen in love with a property but then also say you plan to build something bigger on the land. Which is it?

If you plan to knock down the existing building and build something actually flood-proof then its not a bad idea. There are good architectural techniques for building where floods are certain - foundations more like those of a river bridge, and the ground floor being just garage and a staircase up, and built with materials that won't get damaged by flood water. That would then be insurable.

The flooding will definitely be getting worse over the next few years so past history is no prediction for expected occurrences in the near future. I certainly would not consider buying an ordinary nonspecialised house on a flood plain.

it's false economy.

don't buy it unless you can afford sky high insurance premiums and flood protection.

The current house while very charming is far too small for the long term. The idea would be to live in it for the short term while we got planning permission for a larger house. We would not demolish the existing house but use it as an annex. We've been looking for over a year. If you've ever tried to find a reasonably big building plot in the southeast you know it's not even remotely easy or straight forward and every plot has drawbacks.

In light of your update, no it's a terrible idea. Have you ever been flooded OP? Do you get how awful it is, how much it costs? And the stress each time heavy rain is forecast.

If you were going to knock down and build something raised and floodproofed and you had a plan for replacing your cars periodically that would be different.

You might find it would be more cost effective to completely demolish and rebuild (with appropriate flood resilience) as you won’t pay VAT on a new build. Have you spoken to an architect yet?

If you were going to knock down and build something raised and floodproofed and you had a plan for replacing your cars periodically that would be different

You could always get a floating car platform:

www.duletai.com/product/double-chamber-floating-platform/

(The insurance industry has done a lot of research into UK flooding. With a general conclusion that you shouldn't build homes on flood plains, coupled with an almost universal conclusion you shouldn't trust governments ....)

It's not just building a new property with flood prevention features. The Planning Authority (and the Environment Agency) will be concerned about the impact any new build will have on the rest of the catchment. If you are increasing the amount of built development on the site, this could have a significant impact on the amount of runoff, which could cause problems elsewhere.

I really wouldn't take it for granted that you will get PP - leaving aside the normal issues of getting PP for large isolated dwellings in the countryside (or is it Green Belt - much of the SE is?). In which case, no significant increase in scale will be allowed.

From someone who lost their home to a flood which was predicted to never ever happen don't do it. The stress alone every time it rains is enough to put too much strain on . Don't do it.

Also you have to ask why it is affordable, and that's because most people won't buy it.
Naively I didn't think about what was in flood water, it would have been OK if it was just rain but ofter the sewers overflow, farm storage overflows, animals get washed downstream, we were renting when it happened as between houses, I'm so grateful for the experience as it totally changed my view on floods. Felt very sorry for the owner tho.

I seriously would not do this. Insurance is likely to be hugely expensive. If you do flood in the future, insurance may be difficult/impossible to renew.

Flood zone 3 means a better than 1% chance of flooding in any given year (sometimes referred to as a "1 in 100 flood event") and with increased heavy rainfall events predicted, this is likely to become more frequent than this.

Every time it rains heavily, you're probably going to be worried, keeping an eye on the water levels etc. Is it worth it? I'd say no...

Also, the Environment Agency would object to the planning application as statutory consultees... That's not to say the Local Authority planners would agree with the objection, but they'd consider it carefully.

It’s not even just the trauma of actual flooding or the exorbitant annual insurance or not being able to get insured it’s the constant anxiety every wet night when the rain starts and you are wondering and trotting up to check the stream at midnight, moving the car so that you can get out and not be trapped in by the water, clearing out the ground floor a couple of times a year even though it doesn’t actually happen. Keeping your important documents upstairs so that you don’t lose them. You might say it didn’t flood this year but how many times have you been through the worry of thinking it is going to. It is a constant stress. Wouldn’t do it again!

People who seem to know about these things - would you give the same advice to any house that isn't low risk for flooding?

We were about to put an offer on a house that has low risk from rivers or seas, very low risk from surface water but a risk from reservoirs... the "maximum extent of flooding" map shows basically the whole town destroyed if that happens, I don't believe it ever has, but I know little about flooding and houses 🙈

I think if you can read all of the warnings on here, so periodic flooding of house, possible problems with planning, difficulties with insurance, expense of insurance, possible difficulties with selling and probably not much money made and you still want to go for it, then fine. But at the very least I would be exploring the planning permission issue with the local authority and a planning consultant and then having a plan b in case you don’t get planning at all.

Anchor I imagine the situation you describe is similar to the situation that occurred this summer when a whole village was evacuated for days after the reservoir dam was damaged during heavy rain. It's probably unlikely, but a possibility.

and then having a plan b in case you don’t get planning at all

I think Heron makes a valid point actually. If you don't get planning, and hte existing house is far too small, you may have real difficulties selling as the planning application will have really highlighted flooding issues, as well as other planning concerns. All this will be on public record, so you may have real problems trying to sell afterwards.

We live in a flood zone, the whole area is a flood zone due to the river. my house hasn’t flooded but a few friends houses have very near to us.
Houses that were flooded still sell for stupid amounts of money.
Insurance isn’t a problem at the moment, and it’s comes under the flood re scheme even though the house didn’t flood, but who knows what will happen in a few years time particulary after the 25 year agreement is up.

However it does make me feel uncomfortable, and we have flood doors and aqua snakes ready to use, and the patio doors that will need replacing soon will cost more to make sure they are flood resistant, who knows if they will work.

The environment agency has and is still doing work to divert the river if needed to take some of the strain from the river and the pumping station was upgraded.

But I make it my business to object to planning applications that increases the footprint of the house due to flood concerns, along with it seems quite a few other people.
So far quite a few applications have been turned down due to flooding risk so I would wonder if you would get planning permission tbh.

My dh is a hydrologist.
When we were looking he flatly refused to look at anything on a flood plain.
But we did look at a house that had flooded which was next to a stream. The reason it had flooded was that the culvert where the stream ran under the bridge we tiny, and the water backed up. The bridge and culverts had been rebuilt. Now this house is not low lying, and the stream flows easily and is not a flood risk at all, apart from by the bridge.
Dh loked at the work they had done and did some calculations and asked for the report from the work. He decided it was OK.
(there was a LOT of house for the money, and they were desperate to sell, they had been unable to sell until the fixing work was finished and they put it on the market the day the work was completed, so possibly a massive bargain)

Before we put an offer in we checked the insurance. Most just said no. One firm talked to us about the actual detail, and on hearing about the fixing work, said that they would refer it to a specialist underwriter who would assess the original flood and the remedial works and they make a decision as to whether or not to insure.

At that point we decided not to go ahead, as insurance was obvioulsy going to be an on-going problem, and expensive.

My point is, flood risk can mean a lot of different things in different contexts, you need a hydrologist who knows the area to give you a report. Then you will still face the issue of insurance.

Oh and if your house is isolated you will not be helped by your local council - they only do flood schemes where lots of houses and businesses are affected.

I'm a planner. It's very, very difficult to get planning permission to build in flood zone 3. You also need to figure out if you're in 3a or 3b. If it's 3b, absolutely no way. 3a, you have to be able to prove that you couldn't build anywhere else via a sequential test.

I wouldn't touch it with someone else's barge pole.

Unless you build your house on stilts.
Even so, it's difficult to predict how high any flood will go. See recent floods in Valencia.

@Wildidle can you tell me about the sequential test and by elsewhere do you mean elsewhere on the site?

It's is 3a