Drellingore

...If the buyers really object, perhaps you could apply for a permit (I think £125, takes about 6 weeks) and lean on arguments 1 and 2 - that because you're so far downhill from the sewer, it would have been impractical and unreasonable expensive to connect to the sewer.

The Environment Agency measure the distance to the nearest foul sewer from the boundary of the plot, not where the house is. This means that you cannot meet the General Binding Rules: The Environment Agency say in Form B6.5 (application for a permit), after point 5e2, that: Therefore I believe your system to be in need of an Environment Agency permit, but unlikely to have received one. The installer does not seem to have been familiar with the EA's rules, only with more lenient building control types. Whilst building control might be happy with it, there is a risk for future owners that the Environment Agency find out and take action (not sure what?) against them for having an unauthorised discharge, which I think is a breach of the law. Sorry to be the bearer of potentially bad news. Maybe just give them the fact that it was approved by building control, and hope no-one asks if it has an EA permit? I know that when you intentionally breach a covenant in the title of a property, you can get insurance against anyone ever pulling you up on it. Perhaps the purchasers can find similar insurance about the EA taking action against what sounds like an unauthorised discharge?

We have the choice of both, depending on where we put it. The agricultural land is due to be an underplanted orchard, so tree roots would be a problem. We could use that area for something smaller, like bushes though? Ooh, I'd not heard of these! That could be really handy, as there's a bit of land that a neighbour has right-of-access over for farm machinery. So we can't put anything above ground there, so if we can put in something robust enough to withstand a tractor going over it once in a blue moon, that'd be a really good way of using 'dead' space.

Emailed, had no response. Based on the fact that we haven't got planning permission approved yet, I assumed that BC would tell me to sod off without something much more specific. Besides, the Environment Agency's opinion is more important here, as I need a permit from them owing to being groundwater source protection zone 1.

@Temp that's been a really interesting lead to follow. I've gotten on to National Highways, who don't own it. They put me through to Kent County Council Highways, who have those gullies on their asset register - which explains why Southern Water didn't have them on record. They're going to get back to me to clarify whether it's basically a ditch, or part of some more complex system with proper pipes and stuff. If it's a ditch, that could be a massive win.

Thanks. That's a bit too woolly for my liking when there's quite a lot of money at stake (a cess pool that large will cost about £18-25k and might cost £4k/year to empty), so I need to deal with something more certain - BS6297:2007+A1:2008 seems to be the most authoritative source. I need to apply for an Environment Agency permit, so hopefully as part of that they'll say "cripes, you don't need a drainage field, here's a permit" and then I can wave that at building control later down the line.

Just gonna leave this here

Yeah, it is. Current plans include a second building as as holiday let, but we're beginning to reconsider that (the missus really wants a natural swimming pool instead). The infiltration area is only 47sqm or so, but the total area needed is much larger. We actually have a composting toilet on site (the most complicated thing we've built so far!) so we can spend time there. However, building regs and the like don't seem to take any account of how many toilets are composting. It's all based on the number of bedrooms, and we'd still have other domestic discharge to deal with. Approved Document H2 says that drainage fields are still required for packaged treatment plants. We're actually speccing a PTP with a further tertiary treatment system. I'd be interested if you could point me in the direction of any legislation that says that drainage fields aren't necessary for PTPs. Ooh, that's really, really interesting. That might represent a much simpler solution! I wonder how I can find out more about what the EA define a 'ditch' as. Apologies if I wasn't clear. I need to discharge domestic sewage. There isn't enough space to comfortably fit the required drainage field. There is a surface water sewer (storm drain) adjacent to the property. There is a "land drain" (previous farmer owner's words) that connects my property to the surface water sewer. Our PTP system will output extremely clean discharge (should be 99+% filtration efficiency). Hence I'm interested in finding out if the EA will allow such a clean discharge to a surface water sewer, even if that isn't the norm. I understand that foul sewers and surface water sewers are different things. Thanks, already done all that. Plot is 5 acres (although 3 of those are uphill) but shape is more important. Current design (which is not final) is 12PE. Size of drainage field required is given earlier in this post.

No, it'll cost £1.6m.

Once a drainage field is installed and signed off by building control, what can you actually do on it long term? Is it a case of it's basically 'dead land' that sits there being slightly boggy? Can you realistically plant stuff over the top? If it's designed correctly, would it be boggy at all? Presumably driving over it is a massive no-no.

I just found this thread in a search, and thought I'd answer for future readers. Approved Document H2 references the infiltration area that you need, and not the overall size of the drainage field. In addition to the area required for infiltration, BS6297:2007+A1:2008 says that there must be at least 1m between trenches, and a 1m margin to the sides of the outermost trenches. It is of minor note that Approved Document H slightly contradicts BS6297:2007+A1:2008 in mandating a minimum of 2m between trenches. So assuming the widest trench width mention in BS6297, the formula for width is: (num_trenches * 0.9m) + (2m) + (num_trenches - 1m) Depending on the number of trenches in the design I'm working on, the overall area can be 2.3x to 5.2x larger than the infiltration area.

No, this is treated domestic sewage, and so would require a drainage field/mound rather than a soakaway. The reason I'm looking into use of this land drain that connects to a surface water sewer is because we're struggling to fit the drainage field somewhere sensible - we're currently looking at something 111m2 in total.

Ta, it's the surface water sewer that our land drain connects to that I need to find out more about (who owns it, can I discharge to it, where does it discharge, etcetera).

Cool, thanks for the suggestion. In that case, there's nothing on record, as it's the same system that Southern Water referred me to. How curious! Any ideas how to track down the owner in these circumstances?

For what little it's worth, this is how I used to run my IT consultancy. Daily rates, no fixed-fee work, complete and utter transparency as to what my team were doing at any point, with zero-notice termination if we don't keep the customer happy. It kept the difficult customers away and avoided a huge amount of faff. I doff my cap to others doing business the same way.

Any ideas how to get details on surface water sewer systems, particularly their layout and any infiltration? It turns out that a previous tenant of my plot had a "land drain" installed that leads to the surface water sewer that exists alongside an adjacent road. Local folklore has it that this surface water sewer infiltrates under another field (not under my plot). I've been looking at various domestic sewage options (it's complicated: groundwater source protection zone 1 means I need an Environment Agency permit), and was wondering if I can make use of this drain, if my discharge is clean enough. No doubt the EA will want to know where this surface water sewer discharges to if I'm going to use it. I tried looking at the asset map of the water company that handles foul sewage in the area, but they didn't have anything on record. This left me with a couple of questions: Are surface water sewers recorded like foul sewers? Who owns them - the water companies, Highways Agency, or someone else?

EDIT - reading comprehension failure on my part

Ta. It seems only foul sewers turn up on the maps, so CCTV survey it is!

Thanks for the reply! Any idea who this might be? It's a bit odd in that there are drains next to the road, and then I'm told that they apparently go under another farmer's field to discharge in a ditch.

Hmm, the plot thickens. It turns out that the farmer who worked the site previously had a "land drain" installed, which appears to be a pipe that connects to the surface water sewer for the road adjacent to the site. That in turn allegedly goes to a ditch about 50m away on the other side of a field. I haven't yet found anything that says I could make use of this. Form B6.5 mentioned discharges to surface water, but it seems to assume that you're in control of the pipe that joins that surface water, as the last 10m is supposed to be permeable. In this instance I don't even know where exactly the surface water sewer drains to, and the chances are that it's not somewhere that I own.

Hi - did you (or anyone else) get any better figures on this? Presumably a surveyor's estimate is going to be required for self-build mortgages, and an estate agent's valuation wouldn't be valid?

Do folks here have informed opinions about the usefulness of Spon's Architects' and Builders' Price Book? I bought a copy last year when trying to do a finer-grained cost estimate, and found it moderately useful even if lots of things weren't covered in it. Certainly quicker than calling a bazillion people for ballpark figures, which is all I needed at that point in time. I just looked at the 2023 cover, and the Tender Price Index is 149.3, compared to the 2022 edition's 132. That suggests prices are up 13.1% averaged across all the things. That sounds about right to me, based on what little exposure I've had to the rising costs of material and labour. Do the better informed netizens of BuildHub think that sounds about right?

Thanks for the high-effort response, @SteamyTea!

Ah, okay. So do you think that in such a situation an LPA would look at the plans, see this ancillary building, pre-empt that someone might try and turn it into a separate residential unit/dwelling, and put in a planning condition preventing it from being sold separately? Or is there some step in the process of splitting a title that involves getting the LPA's approval?

I'd be interested if anyone knows what the physical answer to question two is. Electricity is push rather than pull, right? Appliances don't 'pull' power, you open a circuit and the charge difference on the other side of that circuit then makes electricity flow through the appliance. I probably incorrectly imagine it as the appliance is dammed off from a river pushing water against the dam. In the case of solar PV, what happens when a photon hits an electron if that electron doesn't have anywhere to 'go'? Is there some sort of buffering done by the inverter, or does the electron not get 'knocked off' in first place?