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We use 4 phases from rainwater to flushing the loo with it and they are: Collecting, separating and storing in bulk tank. Fine filtering and storing in barrel. filling the gravity tank in the loft Filling the cistern This is not the only system that is possible but one that works with our property limitations. This design and its controls take into account freezing conditions. We use two 12V pumps run from batteries and PV. Here is our system: We were limited for space and you can use gravity to your advantage Here is the design of the catch pit: A circular chamber with a flat base side entry pipes angled to make the inflowing water circulate around the edges. A Tee set vertically with the branch horizontal. Construction details could be concrete slab and engineering brick sides with manhole cover and frame like ours. Needs to either be under the ground or drained before frosts if using a plastic tank. Ours was 900 internal diameter, really the bigger the more sediment settles, but this is for about 200m2 catchment area. If your going for smaller I would go for as tall as deep as you can. The separated water goes directly into your bulk storage ready for further filtering. Ours has just been cleaned out and I will take photos tomorrow. M

I'm looking for an IBC to expand on the capacity of my water butts. Does anyone know of a source somewhere in North Notts / Derbys ie near Mansfield / Chesterfield? Thanks Ferdinand

This info relates to a DIY rainwater harvesting system, not a commercial system, and therefore the water must not be drunk! You should be careful using rainwater not to mix it with mains (Potable) Water as it is not suitable to drink and you could poison your house supply! To be clear birds poo on your roof and then it rains. However there are ways to elevate the problem in a DIY system so there is no smell or colour problems but it still cannot be drunk! You should not use the recycled rainwater for cooking, bathing or showering. SHMBO will not allow it to be used for clothes washing either. The main uses are for garden watering and toilets, and some people use it for car washing and some for clothes washing (we do not have enough storage). How much rainwater are you going to use on loos? Rough estimates suggest that you use about 70 litres a day flushing loos for 2 people. That's about 25m3 a year. More people more flushes more water... How much rainwater are you going to use in your garden? Well that's a good question and trying to work that out is basically a waste of your time because when its raining you won't need to water the garden. Is it going to rain when you need it is the impossible question to answer. so we used a pessimistic view. Our calculation about storage volume went like this: The averages on the isle of Wight where we are suggest typically 4 rainy days in each month from April through to September, however the actual events over a year are much more uneven. In 2 months, it was assumed no rain for 6 weeks: So 2 people 70 litres a day for a 6 week drought = about 3000 litres or 3 cubic meters. and Garden 200 litres a day for a 6 week drought = about 4200 litres or 4.2 cubic meters. (This was based on 200 drippers supplying plants (no lawns) 0.5 litres a day each) Total requirement about 8m3 Well, we don't have room to store that amount of rainwater so for us it came down to what we did have room for which was about 4.5 cubic meters. If we had the room I would have gone for 10 cubic meters. So this is what our loo water looks like after 4 years: No smell, no clogging up valves no discolouration. and the garden: Yes we run out of rain water, and have a backup from the mains. Based on the volume of water used and the cost of, our DIY installation, we will not save money doing this for many years, however it will reduce our bills going forward for as long as it works and we prefer to use rainwater on the garden. Good luck M

My planning permission contains commitments for installation of solar PV, air-source heat pump and rainwater harvesting. I'm not wanting to go through another round of planning variations so I will install them. However, I suspect if I'd done a full cost benefit analysis then it would be difficult to justify the rainwater harvesting in particular. The solar PV hardware appears to be getting much cheaper (haven't looked at install yet) but the Smart Export Guarantee tariffs don't look particularly attractive (5.6p/kWh). ASHP makes sense I feel as there is no gas supply available to site although some of the installed prices appear astronomically high (e.g. £11-12k). Does anyone have any evidence that these eco features more than pay for themselves in purchase premium on a house sale making them "no brainer" territory?

Recently completed a fairly large flat roofed extension covered with black EPDM rubber. The rainwater runs off to an existing rainwater harvesting tank. Since the water from the EPDM roof has been connected the water in the tank has become darker - a sort of blackish yellow. Perfectly OK for toilets etc but unsightly. Filters clear. Is this a consequence of newly installed EPDM and if so does it turn clear in time?

Strange. If I have no rainwater draining off site I can get a modest reduction in my drainage/sewerage charges, apparently. But if I have some of it going into a water butt (or rainwater harvesting) that does not apply? See attached or the quote below. Why? https://www.unitedutilities.com/globalassets/documents/pdf/surface-water-drainage---household-2018-web-acc.pdf Is it one of these "spend money on max benefit" things (like targeting insulation grants at the worst offenders), where anybody doing something already will mean a smaller reduction in the load because it is already being diverted in some way? But surely hat would also apply to full use of soakaways... (Presumably one disconnects the butts before applying) Ferdinand surface-water-drainage---household-2018-web-acc.pdf