Collecting Rainwater for Livestock

Collecting Rainwater for Livestock featured image

Before we moved to our farm, I always knew that we’d collect rainwater for our livestock. When visiting my grandparent’s farm and my uncle’s ranch as a child, I recalled they had downspouts that flowed into water troughs. So, when we moved to our homestead in 2002, we immediately put water troughs under two of the downspouts on the barn.

I had no idea at the time, but this was the reason we didn’t see a copper deficiency problem in our goats until our second year. Our well water is high in sulfur and iron, which bind with copper and causes copper deficiency in goats.

When we only had a few goats, they drank rainwater almost exclusively. But as our herd grew, they drank more, and we had to use more water from the well. Because our bucks were in a remote pen, away from the does, they had well water exclusively, which explains why none of them ever lived past the age of three for the first five years we had goats.

barrels for collecting rainwater

After learning that our goats had a problem with copper deficiency because of our well water, we added rain barrels under a third downspout on the barn. It started with one rain barrel that was purchased from the local community college when their horticulture club was doing a fundraiser. We quickly discovered that the barrel would fill with a short summer shower. To increase our storage capacity, my husband cut a hole in the side of the original barrel near the top and added a PVC pipe that goes to another small water tank.

We even had a third tank overflow connected to the second one, but it cracked when the water froze, and we haven’t replaced it yet. If you live in colder climates, you can’t use rain barrels during winter.

The challenging part, however, is figuring out when you have to drain the tanks. Of course, we don’t want to do that. We want to give our goats rainwater as much as possible because it’s healthier for them. We watch the forecast closely, and we don’t drain the tanks until it looks like temperatures will fall so low that it will be able to freeze the water in the tanks.

If you have goats, I wouldn’t really recommend big water troughs like the one in the top photo. That’s perfect for cows and horses, but goats are picky. If someone poops in the water or it looks dirty to them, they won’t drink it. Do I have to tell you what a huge pain it is to clean out a big water trough? And it’s heartbreaking to toss a bunch of rainwater.

On top of that, horse troughs are too tall for Nigerian dwarf kids to drink from. Twice we had kids wind up in one of those big troughs. One wound up with hypothermia because it was fall and already getting quite cold. Sadly, the other one was found dead because he was too small to get out before drowning.

If you have mostly sheep and goats, I’d suggest getting the water collection barrels and using them to fill up buckets. And when putting together several barrels with pipes, you can save a lot more water than you can with a big water trough.

Is a rainwater collection system right for your farm?

Before installing a rainwater collection system on your barn or other outbuildings, there are a few important things to consider:

  1. Local regulations: Check with your local government to see if any regulations or permits are required for installing a rainwater collection system. Some areas may have restrictions on the collection and use of rainwater. And believe it or not, it is illegal in some areas.
  2. Roof material: The material of your barn roof can affect the quality of the collected rainwater. Metal roofs are a good choice, while roofs made of asbestos or cedar should be avoided.
  3. Water quality: Rainwater is generally safe for livestock use, but it may contain contaminants such as bird droppings, pollen, and other debris.
  4. Maintenance: Regular maintenance is required to maintain your rainwater collection system properly. This includes cleaning the gutters and downspouts and checking for leaks.
  5. Cost: The cost of a rainwater collection system can vary depending on the size and complexity of the system. If gutters are already in place, your only cost may be troughs or storage barrels.

How much water can you collect from a roof?

To calculate the amount of water you can collect from a roof, you will need to consider the following factors:

  1. Roof size: Measure the length and width of your roof to determine the square footage.
  2. Average rainfall: Check the average rainfall in your area. You can find this information from your local weather station or online. If you only have rain for part of the year (and snow part of the year), you can do the calculations for each month individually.
  3. Collection efficiency: The efficiency of your collection system will depend on a number of factors, including the material of your roof, the slope of your roof, and the type of collection system you use. A typical collection efficiency for a well-designed system is around 85%.

Once you have this information, you can use the following formula to calculate the amount of water you can collect from your roof:

Water collected = roof size x average rainfall x collection efficiency

For example, if your roof is 1,000 square feet, the average rainfall in your area is 30 inches per year, and your collection efficiency is 85%, you can calculate the amount of water you can collect as follows:

Water collected = 1,000 sq ft x 30 inches x 0.85 = 25,500 gallons per year

This calculation is an estimate and can vary based on the factors mentioned above. To choose an appropriate storage tank size, you can divide the annual amount of water by 12 months, assuming you need that much water.

If you don’t get rainfall 12 months a year, you can do the calculations for the month with the heaviest rainfall to determine what size storage tank(s) you need.

Of course, you can have multiple tanks. If you want to collect as much water as possible, I’d suggest putting a tank on each corner of the barn.

Tips for creating your rainwater collection system

To get started with rainwater collection from the roof of your barns, you will need to take the following steps.

Calculate the amount of water you need

Determine how much water you need for your intended use, such as watering crops or livestock. This will help you determine the storage tank size you will need. We lose a lot of rainwater because we bought 55-gallon barrels, having no clue how quickly they’d fill up and be overflowing. Unfortunately, it’s not unusual for us to use all the water before the next rainfall.

Install the collection system

Install gutters and downspouts on your barn roof, if needed.

Install a storage tank

Choose a storage tank that is large enough to hold the amount of water you need. Install the tank on a level surface and make sure it is securely anchored. If it’s not anchored, livestock can easily push it over and break spigots when the barrel or storage tank is empty. (Been there! Done that!)

Maintain the system

Regularly inspect and maintain your rainwater collection system to ensure it is functioning properly. Clean the gutters every fall so that the water flows through the gutters rather than overflowing.

Drain the tanks when temperatures are expected to fall a few degrees below freezing.

For more information

Originally published on August 24, 2017.

Collecting Rainwater for Livestock

24 thoughts on “Collecting Rainwater for Livestock”

  1. Great information, however, I think it should be mentioned about roof type. Asphalt shingle style roof I wouldn’t use for animal water. It may seem obvious but not necessarily to someone new 😉

    • Hello everyone, we have a large hay barn and part of the roof from which the water runs off is corrugated asbestos. Is it a stupid question ask if this water can be used for animals and even to water veggie crops? I’d really appreciate your thoughts. Thanks, diolch (from Wales UK)

      • You definitely should not use the water for anything because asbestos is a health hazard to humans and animals.

  2. How do you keep the water fresh so it doesn’t grow bacteria. I usually clean out my bowls daily and put fresh water in. I too have a well with hard water. My wether developed Urinary Calculi perhaps the hard water contribututed to this. I would like to switch over to rainwater cause I know it would be so much better for them. But, I am worried about the water getting nasty setting in a barrel for weeks at a time.

    • That’s never been a problem. As far as I know, the only thing that grows in our rain barrels is a little algae, which has never been a problem. The water isn’t really sitting in the barrel for any length of time as we are constantly using it, and rain is refilling it or over-filling it.

  3. I was told not to use rain water from a galvanized metal roof, is this true? My goats will prefer rainwater even if there is dirt in it over their drinking water which I give clean twice a day.

    • Theoretically there could be zinc in the rainwater that comes off a galvanized roof, but I’ve read about lots of people with galvanized roofs using the water and have heard no issues. One thing I read said that high levels of zinc can act like an herbicide, so if the rainwater isn’t killing the grass and plants where it washes off the roof, then it’s probably not too high. We have galvanized roofs on our 3-sided shelters and often put a water trough under it to catch runoff and have not noticed any issues. Our barns have painted metal roofs.

      • What did you paint your metal roof with? I am looking for a good paint/coating for our rusted metal roof. But I want something safe for the goats.

        • Hi Heather
          I’m so sorry that I do not have a suggestion for you.
          Deborah’s metal roof came already painted.

  4. What do you do in the winter time for water for your goats? I have just restored a barn, plan to put gutters and a rain catchment system on both sides, but am wondering about my well water when it gets cold again. (We live in Michigan). We dug a well, have high iron and sulfur levels in the water, and I am trying to find a simple filtering system for winter time use.
    Thanks! Good article!

    • There is nothing simple that gets rid of iron and sulfur. We tried so many different things and finally bought a chlorine injection system that cost a couple thousand dollars. A huge carbon filter then filters out the chlorine.

  5. We have used a rain barrel for our goats for 4 years now. Perhaps we didn’t construct it properly because the output pipe is on the lower side of the barrel instead of the bottom. We can never drain it completely. We now have what look like worms, but research shows they may be midge larvae reproducing in the bottom of the barrel. I am hesitant to let my goats drink the rain water now. However, our well water is very high in iron and I’m having copper deficiency symptoms. What would you suggest be our first steps? I’ve read your article on capper deficiency in goats. Thank you for all the wonderful information!

    • The worms in the water are not goat worms, so I wouldn’t worry about them. Most goat worms are invisible to the naked eye, and they an only survive inside of a goat or on pasture if it rains often enough so that they don’t dehydrate. For there to be goat worms in the water, the goats would have to poop in the water, which sounds impossible in this scenario. If the worms creep you out, maybe try using a wire kitchen colander to filter them out?

  6. What about the normal “stuff” found on a Gs life leaves, dust and especially bird droppings. Are those not to be considered a health issue with goats or other animals? I had originally planned all roofs with the idea of collecting the rain water but those concerns have kept me from actually using that water.

    • This has never been a problem for us, but I almost never see a bird on the roof. If we lived near the ocean and had 50 seagulls sitting on the roof and pooping, I wouldn’t do it. And you will have leaves and dust in your water, even if it is not rain water.

  7. My question has always been, is it a problem if you can’t clean out your rain barrel either because it is too big or really hard to clean. I just worry about algal growth, mould, what-have-ya, building up inside. Is this something to be concerned about? Should you flush the contents of the barrel on a regular basis?
    Thank you

    • We have never cleaned our rain barrels. As far as I know, the only thing they have growing is algae, which is not a problem. We clean out troughs because they wind up with a lot of leaves in them, but that has nothing to do with it being rain water because the wind blows leaves into an open trough.

  8. Suggestions how to prevent mosquito breeding grounds from forming? (That is probably what the “worms” mentioned above are.) Here in Michigan it is either mosquito season or frozen…

    • That’s a good question. I don’t know why we don’t have a problem with mosquitoes in our water troughs. If you do, then rain barrels would be the best option for you because they can’t get in there. It is a closed system.

  9. I hate to have to mention this, but given the changing world we live in….
    Many state and local governments now have restrictions on how much rainwater you can collect, and in some it is illegal to collect any at all. I know two people who have been fined. They had no idea laws had been passed where they live restricting rain water collection. Please check your state and local laws.

    • Someone else mentioned this to me recently. She’s in Colorado. Where are you located? Or where have you heard that it’s illegal?


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