Water mains running through garden - would you buy?

[B1rdinthebush]

We've just received searches back on the property we are buying and have discovered that there's a whacking great water main running down the left hand side of the house and garden.

This poses a problem as we were planning to put a large side extension on the property which we now can't do. We're now looking at how we can extend to the front and rear (though nothing can be within 5m of the pipe) instead.

But even if we can extend, are we mad to buy a property with a water main running through the garden? My MIL lives around the corner so I know they haven't had to dig up any gardens to access the mains in the 40+ years she's lived there's so I'm not hugely worried in that respect. But part of me just worries it's a burden having it on the property and might put off future buyers?

@B1rdinthebush mine was lovely too. I felt very lucky.

@B1rdinthebush That's great - are you going to go ahead then?

It does sound like the price of the house takes in the water main issue, If I had to compromise on water main v 5 years more mortgage, I’d choose the water main!

I’ve worked for a water company. Both on potable water and sewerage.

Water mains move and when they move they are more likely to burst. The mains will move with changes in temperature to the ground. So you might find that after a big frost, the ground thaws and the pipes move causing a burst. Mains can also be burst due to the age of the pipe or work going on upstream in some cases due to changes in pressure.

A 15 inch main is a pretty significant main. Which means that the main could be pressurised, so a burst main would be larger than just a small leak. If a main bursts, the water company will repair it, regardless of what time of the day it is. Courteous water companies should apologise for any noise but they won’t stop working if it’s 2am or if you’re ill. The size of that main, will mean there are a number of properties supplied from that property and those will take precedent. Access will always be required in case of a burst.

Just because the pipe hasn’t burst previously, doesn’t mean it won’t in the future. The main is old. It could be scheduled for a replacement, so scheduled maintenance or it could burst due to any of the other factors. It might be fine for another 60 years. If the main does burst and your house is flooded, you’ll likely be able to click on the company’s insurance but that doesn’t take into account the inconvenience or the emotional side of a burst occurring on your property.

You might also want to check with the water company if that is best estimate of location or if the main has GPS surveyed. Records in the 50s were hand drawn, they’ll have been digitised by someone (this was my first job straight out of uni). The main may have moved or records may not be accurate. The conditions for access will be based on the location of the main, not the search results.

The downsides of a potential burst main on the property might not outweigh the benefits of the house but you should go in with your eyes open. Just because your MIL hasn’t known the pipe to go, doesn’t mean it won’t.

@fourmonthstogo I think so! Going to speak to the water board tomorrow to get some reassurance that our new ideas are doable and then we should be OK. One thing that definitely made me feel more at ease was that when I walked in, I still had the feeling I had the first time we visited. It just felt warm and lovely and like home. I've never really got that from a house before so I think that says a lot.

@TipsySquirrel Thank you for the info, really informative. As I said upthread, my husband is an HVAC project manager so very experienced with all this stuff (which is reassuring). One of the questions we will ask the development team tomorrow is exactly where the pipe lies as we won't go off the plans we've been given.

Whilst we are aware of the risks of a water pipe bursting or requiring maintenance, I think the thing that worried us most was the lack of scope in developing the plot. However, having been back to the house today we feel comfortable that we have some viable alternative options.

It might be worth speaking to the water company and see if the main could be diverted. Although it would probably cost £££££.
We have a 9inch public sewer running across our property in pretty much the same way that the water main in your diagram does. Our side return extension is 18inches narrower than previously planned as it couldn't be diverted (it serves the school behind us).

will you adjust the offer based on the finding, not able to extend as you wished.