How to Winterize Rain Barrels


Just in time for winter, we're here with tips on how to protect your rainwater catchment system (and drip irrigation gear!) from the frosty weather. Read on for three ways to winterize rain barrels, depending on your climate zone!

winterize rainbarrels snop-capped barrels
Snow-capped barrels! Photo courtesy of BlueBarrel customer Tom in Glastonbury, Connecticut.

How to Winterize Rain Barrels:

We serve customers all over the USA and Canada, so weatherization techniques will vary depending on your climate zone. (Click here for our nationwide network of barrel pickup locations.)

The general recommendation is to follow local protocols for outdoor plumbing in your region:


In areas with light intermittent freezes (e.g. many parts of California), there may be no need to winterize at all. Water tanks, barrels, and even PVC plumbing lines will tolerate temperatures below freezing if the water doesn’t have time to freeze solid.

dripping faucet
A slow-drip can keep water from freezing short-term.

SPECIAL TIP: If your pipes are unprotected and you fear they'll freeze and break on especially cold nights, you can leave a slow-drip in the faucet or drain valve. Moving water requires much colder temperatures to freeze, so allowing a slow-drip will offer some protection. Just don't forget to shut off the tap when the sun comes out in the morning!


In colder climates, plumbing lines can be insulated with standard pipe insulation, available in hardware stores and home improvement outlets.

If you are insulating other outdoor pipes, it's probably a good idea to insulate the underplumbing on your BlueBarrel System, too.

Pipe Insulation

Standard pipe insulation can keep pipes from freezing.


In areas that experience deep freezes (e.g. if you're ice skating on the local lake!), it is recommended to drain rain barrels and detach from downspouts during the coldest months of the year. To protect all parts from freezing temperatures, make sure all ball valves are fully drained as well.

We now have winter covers available under tools & accessories in our online store.* These will restore your downspout to normal function when you disconnect your rain barrels. Order winter covers along with a 1-12" twist plug (also available from our Tools & Accessories menu) to cap the exposed inlet hole in your barrel. Just don't forget to reattach in time to catch the spring rains after the danger of deep freeze has passed!

See BlueBarrel's Maintenance & Operations Manual for more details about weatherizing and maintaining your BlueBarrel Rainwater Catchment SystemTM.

*The winter cover is compatible with our current downspout diverters. If you ordered your RainKit after August 15, 2015, then it will be compatible. If you ordered before then, to disconnect your diverter, simply remove the inlet hose and plug the hole—both in the diverter and in your barrel—with the 1" Expandable Twist-Plugs, available in our online store.
rain barrel plug

1.5" Expandable Twist Plug caps the barrel inlet.

Winter Cover

Winter cover restores downspout when disconnected.

About Winterizing Drip Irrigation Systems:

Many of our customers pair their rain barrels with a gravity-fed drip irrigation setup—another one of our specialties! Of course we need to consider how to winterize drip irrigation systems as well. Drip irrigation line is more flexible than PVC and not quite as vulnerable to freeze damage. That said, all materials suffer over time with extreme weather exposure.

Rolling up and storing irrigation lines during your off-season will prolong it's life, but it may not be absolutely necessary.

At the very least, make sure your irrigation lines are fully drained if you're expecting hard-freezes. If your system has an obvious low-point (or points), you can drain the line from there. On a flat site, lift the line a few feet at a time until all water discharges at each line's end.

Whether or not you decide to roll up your line, if you are draining your rain barrels to prevent freeze damage (see above), you should also remove any ball valves, filters, and timers that connect to your irrigation line. Shake out any water, and store those for the season—the moving parts can get damaged if they contain water that freezes.

Gravity-fed irrigation systems are remarkably simple and don't usually include pumps, pressure regulators, or vacuum breakers, so you have less to worry about. But if you have a pressurized system with more bells and whistles, here's a resource from PennState Extension with full winterization guidelines for drip irrigation systems.

Want to build your own BlueBarrel System?

Visit to size and site your BlueBarrel SystemTM. Then enter our Online Store to customize your RainKitTM and find recycled barrels for local pickup.

Check out our photo gallery for inspiration, and contact us if we can help you with your order as you get ready to collect winter's rains!

DIY Files: Can I Stack Rain Barrels? Everything You Need to Know

Vertical Stacked Rain Barrels

This isn’t an approach we’d recommend. Do you know why? Read on!

It’s one of our most frequently asked questions: Can I stack rain barrels vertically?

The quick answer is yes. But there’s a but. A big one.

While the BlueBarrel Rainwater Catchment System in its classic form consists of one long line of barrels (you choose how many), some people have spatial constraints that lead them to seek space vertically. 

Barrels can be stacked to maximize space, but with each barrel weighing upwards of 500 lbs when full, it’s not feasible to support the weight of one barrel directly on another.

As a second point, if you wish to enjoy the advantages of an under-plumbed design like BlueBarrel’s, you’ll need space between each layer to allow for the plumbing, and proper ventilation.

To illustrate our recommendations for a successful stacked-barrel design, we’ll highlight an example, sent by customer Michael Nunn of Daytona Beach, Florida.

Thanks for sharing, Mike!


How to stack rain barrels

With Mike’s well-detailed diagrams, we were able to work with him to refine the plan and make sure he received all the necessary pieces in his custom-packed BlueBarrel DIY RainKit to build his custom design.

Vertical rain barrels

This diagram, provided by BlueBarrel customer, Michael Nunn, shows the key features of a safe and efficient vertical rain barrel setup.

Here are the key features of his design:

  • Each layer of barrels is supported by its own foundation. At 500 lbs per barrel (when full), a structurally sound foundation must be built to support the weight of each barrel.
  • Each layer has its own downspout connection. The specialty downspout diverter included with BlueBarrel’s DIY RainKits is designed to handle inflow as well as overflow. If installed with a level hose, as shown in Mike’s diagram, water will divert into the barrels until they are full. When barrels reach capacity, excess water will fall through an internal spillover to exit the downspout as normal. There’s no on/off switch for this – it happens automatically with this simple but brilliantly designed piece. In Mike’s case, the second diverter will catch most of this overflow to fill the bottom row of barrels. 
  • There is a shutoff valve between levels. Each barrel in a multi-barrel system must be vented so that air can escape as barrels fill with fresh water. If all barrels are connected via the underplumbing and served with one diverter at the top, water from upper levels will push out through the vents on the lower levels, keeping them from filling. Note the placement of the isolation valve. The valve will remain closed while barrels fill so that both levels can hold water. As Mike uses his water, the top barrels will drain first. Once the top set is empty, he can open the valve to access the water from the lower level. (Another possibility is to have a separate outlet on each level, so that no valve is necessary. In other words, build two separate BlueBarrel Systems, one on top of the other.)

Compliments to Mike for a job well done, and for sharing images with us as well. Here’s his finished project, now keeping his koi fish pond topped up with clean fresh water between Florida storms: 



Why not lay rain barrels on their sides?

stack rain barrels

What’s wrong with this picture?

Here is a design that is commonly found on the internet. Why not do it like this?

There are a number of reasons we recommend the underplumbed design instead:

  • With the bung openings offset a few inches from the edge of each barrel, laying drums on their sides leaves a substantial “belly” in the bottom of each barrel where water cannot be accessed. Multiply that loss by the number of barrels in your stack and that’s a lot of inaccessible water.
  • In addition to leaving water inaccessible, this belly will collect a sludge layer that can create turbidity in the barrels, leading to a heavy load of particulates in the water at the outlet. An underplumbed design flushes most sediments in real time, leading to naturally cleaner water. (Click here to learn why you want those little organic particulates to get to your garden rather than collecting in your barrels!)
  • With no ability to vent any barrels but the top one, and a narrow connection from barrel to barrel, it is unclear whether the bottom barrel will fill smoothly. A vent hole is necessary to allow air to escape as water enters, but unless carefully monitored and controlled, a vent hole in the bottom barrel would allow water to escape, preventing upper barrels from holding water.

Got a special situation, or need help customizing your BlueBarrel System? The knowledgeable team here at BlueBarrel is happy help you for a successful experience with rainwater harvesting. Give us a holler! We’re here to help. 

To First Flush, or not to First Flush

An exploration of the first flush diverter by Jesse Savou, ARCSA A.P., Founder of BlueBarrel Rainwater Catchment Systems

To First Flush or not to First Flush: It's a topic of much discussion in the rainwater harvesting world. A first flush diverter (also known as a roof washer) is a simple contraption that diverts the first flow of water away from a rainwater catchment system. The first pass of water in any storm essentially washes your roof of all the sediments that have collected since the last rain. The idea is that diverting the first flush can help ensure cleaner water in your rain tanks or barrels.

Sounds like a good idea, right?
It turns out many rainwater harvesting professionals don't think so.
As a case in point, all 5 panelists at the American Rainwater Catchment Systems Association's national conference in 2013 agreed that they prefer not to use first flushes. In a separate session of the same conference, keynote speaker Barnabas Kane of TBK Design also highlighted his distaste for first flush diverters, noting that over the years he's been hired to remove more of them than to put them in.
First Flush Diverter
In this photo, the straight-pipe to the right of the tank is a first flush diverter. Water enters the straight-pipe first, and as sediments sink to the bottom, additional water spills over into the rain tank.

So why wouldn't we use a first flush diverter if it's so easy to do?

In fact, there are many reasons:


1. First flush diverters need to be sized correctly for optimal performance, and this is difficult if not impossible to do.
There are many variables that go into determining the optimal size for a first flush diverter. These include rainfall intensity and duration; length of time between rains; roof size, slope, and material; gutter size; wind direction and speed; and air quality. Since most of these factors can vary tremendously even in a single location, you may find that the "optimal size" for your first flush diversion is different for every storm.  And yes, a mis-sized first flush is a bad thing:

If your first flush is too big, you limit your ability to fill your collection tanks. Rainfall abstraction refers to the amount of water that is prevented from reaching your rain barrels or tanks. You can use a rainfall calculator to figure out how much water your rooftop generates, but you'll have to subtract the amount that a first flush diverts... every single time it rains.

If your first flush is too small, the unit will be overwhelmed and sediments will enter your primary storage anyway. In fact, if you have accumulated sediments in your first flush diverter from prior storms, you may even introduce extra particulates to your rain collection system. And this leads us into the maintenance issue...

healthy plants and soils
The organic matter that accumulates on your roof between rains is actually good for your plants and soils. Why divert what amounts to a light application of fertilizer? (See #5.)
2. A first flush diverter is the only part of a rainwater system that requires significant maintenance, and if neglected, it can worsen the problem it aims to solve.
Luckily for most of us, non-potable rainwater catchment systems are amazingly low-maintenance. However, first flush diverters must be cleaned out regularly in order to serve their purpose, and in fact should be emptied prior to every storm event to prevent mixing diverted ("dirty") water with fresher flow. Professionals have witnessed that even the most well-meaning user will neglect this maintenance and reap the consequences.
First flush diverters can be designed with a continuous drain to eliminate the need to empty between rains, but with so much "bleeding," this can be a liability, especially in climates with light rains and/or long dry seasons. It is like having a constant leak that draws water away from your rain tanks or barrels.
3. First flush diverters create a weak point in the conveyance system.
A first flush diverter is usually made of exposed pipe material. This makes it more vulnerable to physical impacts and freeze-cracking than other parts of the rainwater catchment system. Since a first flush device is "upstream" of the storage tanks by design, a damaged first flush will divert too much water—and potentially all water—from the storage vessels. This will result in slow fill rates, or even empty tanks.
4. You have to screen the water anyway. Does a first flush diverter provide additional benefit?
Many states have adopted code to establish simple standards for building safe and effective rain catchment systems. In the state of California, for example, one key requirement is that systems must be equipped with a "debris excluder" (e.g. a leaf eater), and in fact all openings must be protected by 16th" mesh, including the inlet.  This mesh keeps particulates from clogging the system, and also prevents the entrance of insects and other small creatures. If the code requires screening as the preferred method for rough-filtration at the intake, what we're left to determine is whether there's significant additional benefit to adding a first flush diversion.
This photo shows a debris excluder ("leaf eater"): the white screened box that prevents debris from entering the rain barrel system. These rain barrels are used for garden irrigation, so there is no need for an additional first flush. The clear plastic inlet hose can be manually detached if the user wants to divert the first rain of the season.
5. It turns out plants actually like the organic matter that the first flush of rain delivers.
If you are harvesting water for irrigation use (as most of our customers do), the plants actually benefit from the organic accumulation that the first flush delivers. Why go to the effort to divert what amounts to a nice fertilizer mix? In the case of non-potable rain catchment systems that are used primarily for garden irrigation, a first flush may be attempting to solve a problem that's not really a problem.
6. It may be easier to divert the first flush manually.
You may find that only the very first rain of the season is dirty enough to justify diverting. Rather than losing all that water in subsequent rains, take the control into your own hands and remove your downspout diverter while the first storm washes your roof. This may be one of the world's greatest ironies, but if an automatic first flush requires manual emptying after every storm, the manual first flush method described here requires less manual input than the "automatic."

Decide for yourself, but all in all, at BlueBarrel we find that first flush diversions are just that: a diversion. With the benefits so questionable, why not focus on what really matters: collecting the abundant fresh water source that falls on your roof. You have no time to lose!