Bio treatment unit advise please

[MrsB]

I'm hoping for some shared knowledge please being a complete newbie. We are in the process of buying a plot with a barn on that needs renovating. It has PP and the plans state 'foul water drain leading to new bio treatment unit' we have seen a tap on site too. Can I assume we will not need to connect to the main sewerage system? Julie 

[Jeremy Harris]

I'm afraid you can't assume anything!  The tap is an indication that there is, or has been, a water supply in the past, but you don't know if it's capable of supplying a house, or that it's connected to a main.  Your not allowed, by law, to connect to a communication pipe, so if the pipe feeding that tap is fed from another property, via a communication pipe, then you almost certainly can't use it.  You'd need to trace back to where it originates to be sure.  If it comes from a stop cock near the road that has a cover marked with a water company logo, or just marked "water", then the chances are it's a mains connection.  In that case you just need to enquire from the water company as to whether there is capacity available for you.  If their answer is no, then they are obliged to put that extra capacity in, but may well send you the bill for it.  It's a thing that should be resolved pre-purchase, as it can be very costly (our water supply costs were going to be £23,500, even though the house over the lane has a pipe that runs 2m from our plot).

 

Mains drainage plans are available from your water company, and show the position and invert depth of the nearest manholes.  They will usually let you have a copy of these free on request.  You can see if it's feasible to connect to a main drain from those, remembering that you can run sewerage uphill using a pump if need be. 

 

Whether you can fit a treatment plant depends on the soil conditions and the amount of space you have for a leach field.  Some soils just won't drain well enough for a treatment plant to be fitted.  The planners will happily grant planning permission that says the house can be built with a treatment plant when one cannot be installed in practice, we found!

Edited February 9, 2017 by JSHarris

[MrsB]

@JSHarris thank you for all that information, I really appreciate the fact I can ask and be given honest feedback that enables me to investigate (sadly this is often due to other misfortune in the past with the same issue). 

 

I'm sure there is a water meter at the entrance to the property but I will check that out and follow your advise.

 

The plot is large enough to accommodate a bio treatment unit but I need to question if the ground will accomodate it's drainage

 

julie 

 

[Jeremy Harris]

It's worth a call or email to your local water company new connections team.  Mine came out within a day to do a site survey and price up the connections, long before we made an offer for the plot, and then emailed me plans showing the location of both water and sewage mains, together with the connection costs and confirmation that their network had the capacity.  The costs were very high, around £14k for sewage and £23.5k for water, after I'd deducted the part of the quote that was for work that could be done by others and got separate quotes for it. 

 

Worth asking for a breakdown of any quote from a utility co, as they are obliged to split it into two parts, the general trenching and surface reparation work that can be done by any approved/competent company and the connection which can only be done by them.  Often there are ways to get the trenching, pipe/cable laying and surface reparation done for less cost than the utilities quote, especially if you already have a ground works company lined up for other work on site who have the appropriate approvals to do such work.

[ProDave]

IF there is no mains drainage available, then what you (or the seller) needs to do is perform a "percolation test". It's well documented in the building regs handbook. Basically you dig a 1 metre deep hole. In the bottom of that you dig a 300mm by 300mm hole 300mm deep. You fill that with water and time how long it takes for that water to drain away. That's a bit simplified but that's the general principle.  From that, and the number of occupants that the house is designed for (a different figure to how many will actually be living in it),  you calculate the area of leach field required. That can end up quite a large area. and there are restrictions how close the leach field can be to the boundary, buildings, the road, a watercourse etc which further limits available space.  Then you need to see if that leaves enough space to actually build a house.

 

If the ground is not suitable, e.g. if the water table is very high, then there are alternative above ground solutions such as a filter mound, or the Puraflow system that has tanks filled with peat above ground.

 

We ran into this problem with our plot. we bought it and went through planning on the basis we could fit a filter mound system in. In the intervening time, building regs changed, and the distance from a road to the filter mound changed meaning we no longer had room for it. Eventually SEPA gave us permission to discharge to the burn, something they only do up here if there are no other options, and we had reached that point of having no other options that building control would accept.
 

[MrsB]

6 hours ago, JSHarris said:

It's worth a call or email to your local water company new connections team.  Mine came out within a day to do a site survey and price up the connections, long before we made an offer for the plot, and then emailed me plans showing the location of both water and sewage mains, together with the connection costs and confirmation that their network had the capacity.  The costs were very high, around £14k for sewage and £23.5k for water, after I'd deducted the part of the quote that was for work that could be done by others and got separate quotes for it. 

 

Worth asking for a breakdown of any quote from a utility co, as they are obliged to split it into two parts, the general trenching and surface reparation work that can be done by any approved/competent company and the connection which can only be done by them.  Often there are ways to get the trenching, pipe/cable laying and surface reparation done for less cost than the utilities quote, especially if you already have a ground works company lined up for other work on site who have the appropriate approvals to do such work.

 

@JSHarris Thank you for the input today, I was staggered by the amounts you have quoted 23.5K for water which we wrongly assumed was available. I've started my research and will give my water company a call in the morning to start the ball rolling. Lesson learned today , don't assume anything :0/ 

Edited February 9, 2017 by MrsB

[Jeremy Harris]

It's fair to say we were pretty staggered, too! 

 

The original quote from the water company was around £26k, IIRC, we got it down to £23.5k by getting separate quotes from other approved contractors to dig the trenches and do the surface reparation work. 

 

As I mentioned above, all the utilities should break their quotes down into two parts, the contestable element (trenches, surface reparation, pipe, duct or cable laying) that any approved contractor can do (often cheaper than the utility companies) and the non-contestable element (making the actual connection to their network, testing, doing any work required to their network to accommodate the increased demand, etc).

[PeterW]

1 hour ago, MrsB said:

 

@JSHarris Thank you for the input today, I was staggered by the amounts you have quoted 23.5K for water which we wrongly assumed was available. I've started my research and will give my water company a call in the morning to start the ball rolling. Lesson learned today , don't assume anything :0/ 

 

You wait til the electricity companies get involved ... we paid £1150 for 2m of connection to a LV main in an unmade road ..!

[Jeremy Harris]

The electricity connection was my only lucky break.  By relocating the big 3 phase cable right under the meter cabinet, and leaving the trench open over the top of it, I only paid £300 for the connection, which I think is their minimum charge.  It took to chaps two hours to do, but part of that was having a break whilst the potting cured around the underground joint.............

[MrsB]

@PeterW @JSHarris thank you. I've been in touch with the electricity company and am awaiting a call back within the next 2 working days, then no doubt another wait for the quote. This game seems to be a lot about waiting!

I began to wonder if I was doing the right thing yesterday evening (getting cold feet) but I'm hoping the advice I get from you guys plus the never ending rewatch of home renovation TV programs will at least prepare me for the rough road ahead.

One of the fun things we discussed was using a drone (we have 4 acres) to record our progress as well as the conventional photo/videos of progress made once we own the land ? Julie 

[PeterW]

For drones you need to talk to our own aerial photographer @Construction Channel

 

Does the site not have existing power..? Being rural you may find its in a pole transformer - these do need replacing and upgrading over time and sometimes you can get lucky and the company will do it for free. Other times then you may end up with a bill - £10-15k is not unreasonable. 

 

It also drives the decisions on what to use for heating etc as unless you go very low energy you will need to get a decent heat source that is not power hungry or the price of the transformer goes up ..!

 

@readiescards did some thinking on being off grid in a similar situation 

[ProDave]

3 minutes ago, PeterW said:

Does the site not have existing power..? Being rural you may find its in a pole transformer - these do need replacing and upgrading over time and sometimes you can get lucky and the company will do it for free. Other times then you may end up with a bill - £10-15k is not unreasonable.

That is a valid point. we were only offered a "12KVA supply", which is a bit low for a normal domestic house, but that was on the basis of there being 8 houses now sharing one 100KVA transformer, and I know if we pushed for a bigger supply, there would have been a cost implication to upgrade that transformer.  The reality is we get exactly the same supply as anyone else,same size cable, 100A fuse, so we could draw 24KVA from it without problem, but if everyone did that at the same time there would be a problem.
 

[MrsB]

Heating @PeterW that's another can of worms I've not even opened yet! I was thinking underfloor on the ground floor then finding an alternative for the upstairs. It's on my 'to do research' list and obviously read on this forum.

 

The existing barn is double story and then the new build running off the barn single. 

[IanR]

19 minutes ago, PeterW said:

Does the site not have existing power..? Being rural you may find its in a pole transformer - these do need replacing and upgrading over time and sometimes you can get lucky and the company will do it for free. Other times then you may end up with a bill - £10-15k is not unreasonable. 

 

I needed new connections to my Barn Conversion, to split it away from the original supplies to the Farm. UK Power Networks made sure I paid for a new Transformer even though I could demonstrate that our Farm and two neighbouring Farms supplied by the same Transformer were not using anything like the power they consumed 10 years ago.

 

Even to add 20kVA single phase supply for my property they wanted the transformer upgrade, so I went with 100kVA 3 phase and it made no difference to the price. The Transformer was £3.5K, but the overall connection was £8.5K including the 130m of underground cable pulled through a trench that I dug.

 

Here's my Transformer, I feel I own it!

 

[IanR]

23 hours ago, MrsB said:

 Can I assume we will not need to connect to the main sewerage system? Julie 

 

Back to the OP.

 

Is there a Main Sewer nearby? The House on the same plot - where does that connect to? If it's economical to connect to the Main Sewer that should be your base line cost, and only go with a treatment plant if it saves you money (including annual maintenance).

 

I didn't have the option as there is no main sewer in the road. I'm also on heavy clay, so it was unlikely that a leach field site would work. However I was lucky with the gradient of the site and that I had a surface water ditch running away from the corner of the property, adjacent to the perfect location for a treatment plant.

 

If you work within the "General Binding Rules", you avoid needing a discharge permit from the Environmental Agency. Not that a permit would be difficult to obtain, I believe you just need to prove that a leach field would not work for your ground conditions. Or if a leach field would work then you don't need a permit anyway. 

 

Here's the rules:

 

https://www.gov.uk/permits-you-need-for-septic-tanks/general-binding-rules

 

Edited February 10, 2017 by IanR

[Jeremy Harris]

Just to add to the above, although we had hassle from the EA on a few things, when I applied for a Permit to Discharge to the stream alongside the plot they emailed me back with the permit within 4 hours!  Not a single question was asked, they just granted it.

[readiescards]

10 hours ago, PeterW said:

For drones you need to talk to our own aerial photographer @Construction Channel

 

Does the site not have existing power..? Being rural you may find its in a pole transformer - these do need replacing and upgrading over time and sometimes you can get lucky and the company will do it for free. Other times then you may end up with a bill - £10-15k is not unreasonable. 

 

It also drives the decisions on what to use for heating etc as unless you go very low energy you will need to get a decent heat source that is not power hungry or the price of the transformer goes up ..!

 

@readiescards did some thinking on being off grid in a similar situation 

A quick summary of going off grid :  its expensive! Suddenly the power consumption of everything matters and it seems to cost a lot to have the low power option - I'm just hoping the thousand pound dishwasher automatically stacks itself as well as using little power!