Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
Septic tanks versus mains sewage
Curious to know who isn't on mains sewage?
Not being on mains sewage takes a level of greater dedication to keeping your sewage systems clean and healthy. We don't have a septic tank. The previous owners put in a home sewage treatment plant, which is great, but requires us to be very disciplined with what goes down the drains and toilets. We have to greatly limit FOGs (fat, oil and grease) as well as chemicals that can kill the bacteria that are breaking things down, which means we have a low impact array of personal (toiletry) and home cleaning products.
This has opened our eyes to the products we used to use when we were in urban environments, and using low impact cleaning products, even if you're on mains sewage, is just so much better for the environment.
Dad’s Outside with the Heat Pump Again
He wanted to save the planet. His family just wanted him to come inside.
Get the book → · Free UK shipping
The Ultimate Guide to Heat Pumps · Britain’s Heat Pump Shitshow
Heat Pumps Explained · From Zero to Heat Pump Hero · Bodge Buster
From Zero to Heat Pump Hero and Bodge Buster are rewritten and updated for 2027.
New to heat pumps? Heat Pump Fundamentals course — 50% off with INTRO50.
Septic tank here. As I understand it, while not as sensitive as a home sewage plant, it's still worth being careful because the better the tank flows and breaks things down so they can go out to the leach bed, the smaller the tank emptying, although the call-out charge dominates anyway. We add dry used coffee grounds or oats to old oil or fat and put them into the food waste collection, not down the drain.
And cloggers like wet wipes (even some that claim to degrade!) need to be avoided because jetting the pipes costs more than a tank emptying.
@mjr, I like the idea of using the coffee grounds to soak up oils. We don't deep fry so never have excess oil in significant quantities. Most of our coffee grounds end up in the compost bin or in plant pots that are home to acid loving plants.
Wet wipes are awful, even the ones that break down as you've said. The other thing we've found that takes forever to break down is kitchen roll. We've now stopped flushing it because it can clog up our vibro filter in the home sewage treatment plant tank. We've also found that Muck Munchers help to slow down and break down the sludge layer.
Dad’s Outside with the Heat Pump Again
He wanted to save the planet. His family just wanted him to come inside.
Get the book → · Free UK shipping
The Ultimate Guide to Heat Pumps · Britain’s Heat Pump Shitshow
Heat Pumps Explained · From Zero to Heat Pump Hero · Bodge Buster
From Zero to Heat Pump Hero and Bodge Buster are rewritten and updated for 2027.
New to heat pumps? Heat Pump Fundamentals course — 50% off with INTRO50.
Another off mains sewage here.
We have a Klargester under one lawn, dealing with the septic waste and a soakaway under another lawn dealing with the waste water from the kitchen and utility room. It was set up that way well before we bought the house and yet Southern Water had the temerity to try billing us for water treatment when they sent our first bill. It took about six months of paper trail (and us refusing to pay until they sent us an appropriate bill) before they started playing nicely.
As for what we put into the Klargester, we’ve never been big on wet wipes and so on anyway, so have never had flushing problems. The biggest problem we found was working out which toilet cleaners are OK to use. Harpic is the only mainstream product we’ve found that declares it’s compatible with septic tanks.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
We installed a Klargester 5 years ago as part of a total renovation project. House was not on mains drainage or mains water at the time.
Our first water bill assumed we were on mains drainage. It took a while to prove to the water company that they had no sewer in our village!
Klargester has been excellent. No smell, no noise. We have an annual maintenance contract. There are only two of us in the house and the sludge only needs pumping out every other year. It drains into a soakaway in the adjoining field.
We are careful to only flush the 3 Ps (poo, pee and paper down the loo), so no wet wipes. We don't use toilet cleaners any differently from when we were on mains drainage. But if I have to clear a blocked sink, for example, I'll always take care to flush with plenty of water afterwards.
We put coffee grounds on the garden, together with what little cooking fat we have.
Mike
Grant Aerona HPID10 10kWh ASHP
Posted by: @mike-patrick...
Our first water bill assumed we were on mains drainage. It took a while to prove to the water company that they had no sewer in our village!
...
Our utility company were similar, but we took a more confrontational approach I'm afraid. They wanted proof of installation and all kinds of other documents, all of which were property of the previous occupants. We simply told them we'd supply an invoice from the waste removal company to demonstrate we had a septic tank and that they'd have to be content with that. If they were content, they could send a revised bill and if not then we wouldn't be paying them anything until we'd received such a bill.
I'm pretty sure they were trying to push the responsibility onto us in order to try and get more money from us, but we were making it blindingly obvious they'd lose in a small claims court and therefore it was in their interests to act reasonably. After all, we weren't trying to avoid paying for legitimate services rendered; just not paying when it wasn't appropriate.
I agree with you that the Klargester has been great. We have a local company that come round once a year to empty it and we don't even need to remind them. The bill is very reasonable and markedly less for the whole year than the quarterly charge the water company were trying to charge us for sewage treatment. Food for thought, eh?
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
- 27 Forums
- 2,817 Topics
- 66.8 K Posts
- 3,183 Online
- 7,230 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
RE: Why don't people choose heat pumps?
I'm still struggling to understand your last sentence t...
By SusannaSaunders , 1 hour ago
-
RE: Heat Geek Zero Disrupt: Are We Sleepwalking Into Another Race to the Bottom?
I couldn't agree more. It's all to easy to get wrapped ...
By Majordennisbloodnok , 1 hour ago
-
RE: Issues with Samsung heat pump – high running costs and house dropping to 11C overnight
It looks very much like a radiator balancing i...
By hml1827 , 2 hours ago
-
I have, @transparent, but chose to pose the question he...
By Majordennisbloodnok , 2 hours ago
-
RE: Should I change my cylinder when changing from a gas boiler to a heat pump.
@jamespa’s point about payback is a useful counterbalan...
By Mars , 5 hours ago
-
If it no longer works after forgetting its settings and...
By bobflux , 6 hours ago
-
RE: Plug and play solar. Thoughts?
Impressions so far from the one I've installed are that...
By EtchedPixels , 20 hours ago
-
-
RE: Air source heat pump roll call – what heat pump brand and model do you have?
@editor And as an occasional contributor, may I say wel...
By Toodles , 1 day ago
-
RE: Should Households Who Can Afford It Pay More for Energy to Help Those Who Can't?
They don't have to try. Our entire system is d...
By EtchedPixels , 1 day ago
-
RE: How Can I Prove Coal Was My Main Heating Source Without Receipts?
Got excepted for the grant now so thanks for the replie...
By Chilli304 , 1 day ago
-
Daikin Altherma 3 R F+W, room thermostat control, weath...
By JanHarley , 1 day ago
-
RE: Buffer tank on a 2 x 14kw Ecodan system
Pretty much as I had guessed in my crude scaling from m...
By JamesPa , 1 day ago
-
RE: Help me keep the faith with my air source heat pump installation
Well you have a vibration generator running at some fre...
By bobflux , 2 days ago





