Does anyone know anything about flooding?

[genieg]

There's a very small stream running along the front boundary (not on the property). We are buying a house and the environmental report has given the property a green rating for flood risk which means there should be no problem with insurance.

However it has a low to moderate risk of surface water flooding..which it describes as a 1 in 200 year rain event risk of 0-30cm flooding due to surface water.

It seems pretty minimal to me but the purchase has been one long headache and I'm getting worried that I'm willing to overlook anything to get the point where we move!

Is there anyone here who has any experience of this?

I have extensive experience of flooding and my advice is do not go anywhere near a property that is near water. We moved into a house years ago that had a stream a field away.
With global warming , something that had a one in 50 years chance of flooding, has flooded every year since 1998. The EA have no money and although they are sympathetic they won't do anything as it only affects two houses.
If you buy this house the stream may well become a torrent through surface water. Also the EA are Gung Ho about their predictions.
The situation has rendered our house very difficult to sell. Ask about insurance as well as if your intended purchase is on a flood plain, then your insurance will be sky high.
Don't buy it!

We have recently pulled out of a property due to the same flood risk. Look at the weather last winter, places that have not flooded previously were under water for a month. Maybe this is the 1:200 year event but maybe not, we wouldn't take the risk and it is likely future purchasers of the property won't either.

I have had a flood at a previous property, water only came in the house for 15 minutes but it caused years of damage and serious psychological issues, i panicked every time it rained hard for several years later.

I understand your position though. I was so in love with the new property that i nearly talked myself into it, but eventually saw sense.

surface water flooding risk means that the area has been overdeveloped with the usual no thought at all to drainage. New build estates have flooded even before they were finished!

run some insurance quotes and see what happens.

it will not be so bad if the stream is downhill from your house, so it has to fill a large area before any rise reaches you; and if the downstream area is unobstructed so it can flow away earlier.

I work for the EA and am a flood risk management engineer.

Surface water is basically rain water on roads that can't drain away, and comes under the remit of the Local Local Flood Authority - unitary Council or county council. Surface water flooding happens when drainage can not keep up with surface water run off. This is common where an area has been heavily developed, although developments in the last 5 years or so have come under much stricter drainage guidance than previously, and are required to improve on natural "greenfield" drainage.

Surface water flooding maps were developed across Europe 3-4 years ago, and are a relatively new thing in property purchases and insurance, but cover everywhere, not just properties adjacent to rivers.

Surface water flooding has always happened, it just has not been quantified before. The Lead Local Flood Authorities will all have a Preliminary Flood a Risk Assessment from July 2011 which identifies where the issues are in their area, and outline plans to address them. I think they also have depths in; it could be that the potential depth of flooding is well below your house's threshold level.

A 1 in 200 year risk is very low for surface water flooding. Turning the stats around, you could so say that it's the same as a 0.5% chance of flooding any year, or a 99.5% chance of not flooding.

Thanks everyone, so hard to know what to do.

We checked out buildings insurance yesterday and got several similar quotes, well within expected range.

However, I'm getting more worried, not less. The risk of flooding at the site is low, its within 25m that it's low to moderate which I guess is the 'stream'. It's more of a ditch which runs with water in the winter/spring months, not year round. Its approx 15m from the house and the land slopes very gently upwards (barely noticeable) and then the house is stepped up approx 40cm from the ground.

Oh what to do. Its a perfect house in every way except for this.

When we moved into our house 30 years ago there was as little stream about a field away, that discharged in to a large river. The house had never been flooded. The village had but the house was farthest away from the main river, and our house was the opposite end to the part that got flooded.

In response to the village being flooded the EA ( it wasn't the EA then) built up the embankment all around the river which now prevents the village from flooding. They then built up the embankment along the stream. They compulsorily bought the land and built the embankment.
With global warming/ increase in rainfall over the years there has been an enormous increase in rainfall and the small stream is now filled on occasion to the brim. There are non return valves at the river end, preventing the stream from emptying into the river until the river has stopped raging. Consequently the water sits in the dyke, the land around gets sodden and my house gets surrounded by around six inches of water. It enters the house just below the floor boards. It is extremely distressing.
The EA staff change constantly and are lovely people without exception but they have not been able to offer a solution because the situation only affects two houses. They just don't have the money.
We are now faced with the situation when we come to sell that we will either have to give our house away very cheaply or not be able to sell it at all. It is truly heartbreaking.
So my advice is don't. Never mind what the EA say. I in 200 years seems remote but if you do get flooded you will never forget it. Also you will not be able to sell your house. You saw what happened to those poor people last year.
When they were crying on the TV, I cried with them. It is traumatising. Sorry

Thanks again hole. I'm so sorry you have to go through that. This house represents all of our investment and life savings so I think we are veering towards pulling out.