Introduction: How I Made My Garden Water Storage System (July 2020)

This instructable will hopefully show how I've managed to create the first part of my water collection/storage system.

My system has grown organically, in that there was no over-arching plan at the start. It has been amended and added to, as and when I thought it needed upgrading/changing etc.

It is quite specific to the layout I have on the property but there might be useful information for anyone considering it.

This is based in Plymouth, UK. People elsewhere might have different rules and regulations which will govern your installation.

*************************************** WARNING **********************************

With any long term storage of water there is always the possibility of nasty things growing in it. This includes but not limited to Legionnaires' disease. You should be aware of this, and think about reducing the risk by including a system for purifying or treating the water on a periodic basis. I do not have anything connected, such as sprinklers, which would cause the water to become small droplets in the atmosphere.


My system is made up of the following, but you will need to decide how much and size of each item for your own requirements.

4 x 1000 litre storage containers (also known as IBC)

1 x 200 litre garden water butt

1 x 100W solar panel (mine is over sized)

2 x 13.5W 12VDC water pumps with max head 4.5m max flow 650 litres/hour

1 x MPPT solar panel charge controller

1 x 12V battery

1 x 12VDC marine float switch

2 x 12V/50W halogen bulbs

plastic bottle acting as float

lengths of 13mm black plastic garden irrigation pipe

lengths of 25mm black pond pipe

concrete blocks

Step 1: Location of Collection Barrel

My collection barrel is a standard (for UK) 200 litre garden water butt and is fed by gutters attached to the shed.

There is only the one barrel here because there's not enough room for me, between shed and property line, to access a second or more.

I get water from one side of the shed via a small plastic tank. To reduce debris blocking the feed pipes, the outlet is mounted above a sediment collection layer, which is periodically emptied. There is a piece of plastic mesh netting to also stop bugs using the water as a breeding site.

The pipe from the small plastic tank goes to the floor, across the front of the shed and then back up into the collection tank.

Water from the second side of the shed goes straight into the collection tank.

Water from the collection water tank is pumped to storage tanks on land above the shed.

Step 2: Moving Water From Collection to Storage Tanks

The collection tank is fitted with two small pumps to move the water. They take 13mm irrigation pipe.

After previous experience, with submerged pumps being messy to maintain/fault find, I've mounted them external to the tank. These pumps run off a solar charged 12VDC battery, more on that later.

So as to reduce wear and tear on the pumps, the water feeds are raised above a sediment collection layer.

The units I used can pump uphill (aka head height) 4.5m above the pump. Their max flow rate at zero head height is 650 litre/hour. My highest storage tank is approx 4.0m above the pumps, which means they don't fill up very fast, compared to if they were at the same level. This isn't of too much concern to me as I want the water to be as as high in the garden as possible, to give me greater pressure in the lower parts of the garden.

The pumps were bought off a website for approx £10-15 (GBP) each. It wouldn't be much use me putting a link, as that supplier/maker may no longer exist by the time this is read. Just look for equivalent.

The collection tank has an external float switch, so that the pumps turn on automatically when the tank is full. I've used a marine bilge pump float switch, for it's durability in wet/damp conditions. Again these can be bought off websites.

I wanted to avoid the pumps being switched on/off too frequently, to reduce possibility of burn out. By using a plastic bottle attached to a lever (copper pipes), I've managed to increase the operating range between on and off. This means that the pumps will move approx 70 litres before they switch off again.

Step 3: Storage Tank Setup

My specific location allowed me to place 4 x 1000 litre storage tanks in two stacks of two.

The tanks I have are translucent. So far, I have avoided trying to cover them in anything, and try to keep plants from climbing up them. I feel if you're going to try and exclude light, to prevent green growth etc. you've got to get it complete. Any light at all getting in will allow growth. I have decided to allow the sun full and direct access to the tanks thereby increasing the exposure to UV. I have had a single stack of two in place for a couple of years now and have not seen any build up of algae etc. Will have to see how it goes with the extra capacity etc. Additional options are available should it become an issue.

The first stack, consisting of tanks 1 and 3, is raised slightly by using concrete blocks. This is to allow water to overflow from tank to tank without any loss in capacity.

The collection pumps feed into the top of tank 1 using 13mm irrigation pipe. The lid is sealed pretty tight, to prevent bugs using it as a breeding ground.

Using more 13mm irrigation pipe I have placed a number of taps around the garden to fill watering cans etc. These are supplied from tank 1, as it is the highest and gives me the best pressure. The pipe run at the furthest is approx. 30m and there is quite a bit of friction reducing the ultimate pressure. I could get more water flowing if I replaced the 13mm with 25mm, but this would also be at quite an expense. If I was thinking of doing this again I'd have to weigh up the benefits v costs of using 25mm throughout.

Once tank 1 gets full, it automatically overflows into tank 2, and so on down to tank 4. I've used 25mm pond pipe fittings for this part, as the amount of pipe is relatively short.

I have added another set of 25mm pipes on tanks 2-4, to allow water to flow back to the collection tank. This then refills tank 1 should supply/pressure get low.

Step 4: Electrical Components

My system is run from a solar charged 12V DC battery.

I have 2 x 100W solar panels at the back of the garden, but only 1 is used in this system.

The panels used to be sloped at an angle to improve the charging efficiency. After installing the second 2 storage tanks, the panels had to be moved to a new location, which didn't really allow for tilting effectively. This is not of too much concern to me as the panel is more than sufficient for the current demands.

The battery I have is a sealed gel type. I can't remember any other details about it and there's none on the battery itself. It is big enough to enable the pumps to run during hours of darkness, as long as it doesn't rain too hard all night.

This system uses a generic MPPT type solar charge controller. It's not that expensive at about £30 (GBP) and was again bought off the internet. More expensive models might give you more features but this one seems to be working.

The charge controller is connected to the solar panels, the battery and a load. The pumps are connected to the battery via the float switch and a secondary over-ride switch.

I added 2 x 12V/50W halogen bulbs to the load side of the charge controller. The idea behind these is, if the panels are supplying voltage, but the battery is already full the controller sends the extra to the bulbs. I've had batteries fail in the past when I haven't had load bulbs installed. It could've been because the system hasn't been designed as a whole, and is not balanced in some way. Whatever the reason I find that this current setup has lasted the longest so far.