Rain Barrels and Gutters: What Actually Works in Wisconsin

How a rain barrel connects to your gutters

You don't replace anything. A downspout diverter is a small fitting that installs into the existing downspout, usually 3 to 4 feet off the ground, at a height that matches the top of the barrel.

The key thing people misunderstand: the diverter does not send all the water to the barrel forever. It redirects flow into the barrel until the barrel is full, and once the water level equalizes, the rest continues straight down the downspout the way it always did. Most kits also have a winter setting that closes the barrel port and sends everything back down the normal path.

That design matters. A good diverter never traps or restricts flow. If you're looking at a setup where the only path for water is through the barrel, walk away. During a July downpour, that's how you get water backing up in the gutter and spilling over the fascia.

How to connect a rain barrel to a downspout

1. Set the barrel on its finished base and measure the height of the lid inlet.
2. Mark that height on the downspout and cut out a short section with tin snips (wear gloves, cut edges are sharp).
3. Slide the diverter in, overlapping the upper downspout section into it so water runs downhill through every joint.
4. Secure with the supplied screws or a couple of zip screws, and reattach the lower downspout section below the diverter.
5. Run the short feed hose from the diverter into the screened barrel inlet, then run the overflow hose from the barrel's overflow port well away from the house.

That's a 30-minute job for most people. Sizes are standardized: 2x3 inch and 3x4 inch cover nearly every residential downspout in Wisconsin, so match the kit to what you have.

Does cutting the downspout hurt the gutters or fascia?

Not if the joints are lapped correctly. The cut is well below the gutter trough, the hangers and the fascia board, so the sealed seams up top are untouched.

Two things do cause trouble. First, a diverter installed backwards, with the upper downspout sitting inside the fitting instead of lapping over it, sends a thin stream running down the siding every rain. Over a few seasons that stains siding and can wick behind trim. Second, a barrel hung or strapped off the downspout rather than sitting on its own base puts hundreds of pounds on a sheet metal elbow and the straps screwed to your fascia. Barrels sit on the ground, always.

What a rain barrel gutter setup costs

Budget $100-$250 for one barrel done properly. The pieces break down like this, and they move with the market:

Where the cost really changes is everything downstream of the barrel. Swapping in a longer downspout extension or a better splash-block run is a minor item we'd fold into a gutter visit. A buried extension trenched out to a daylight discharge point is a different animal: we price that per foot after we walk the run, because depth, soil, sprinkler lines, tree roots and access all change the number. Same with gutters that need resizing because they already overflow.

Is a barrel worth it? For unchlorinated water on tomatoes, seedlings and containers, yes. As a water-bill strategy, no. Municipal water in this part of the state is cheap enough that the barrel pays you back in plant health, not dollars.

The sizing math nobody does before buying

One inch of rain on 1,000 square feet of roof sheds roughly 600 gallons. Run that against a 55-gallon barrel and the picture gets clear fast.

A single downspout might drain 300 to 600 square feet of roof. In a half-inch rain, that section alone can send 90 to 180 gallons at your barrel. Your 55 gallons is gone in the first several minutes of the storm.

So a rain barrel is not drought insurance. What it is:

• Free, unchlorinated water for plants that sulk on city tap water
• A refill station for watering cans so you're not dragging a hose across the yard
• A small reduction in runoff off one corner of the roof

What it isn't: flood control, foundation protection, or a substitute for properly sized gutters and downspouts. In a 2-inch storm, a barrel captures a rounding error.

Linking two or three barrels

If you want real garden capacity, link them. An overflow-to-next-barrel kit runs a short hose from the first barrel's overflow port into the second barrel's inlet, and they behave as one larger reservoir. Two or three barrels gets you 110 to 165 gallons, enough to carry a vegetable garden through a dry week.

Same rule at the end of the chain: the last barrel still needs a real overflow route, and all of them need to sit at the same elevation on a base that can carry the combined weight.

Rain barrel overflow: the #1 mistake

This is the one that costs people money. A barrel that overflows straight down beside the house undoes the entire purpose of having gutters and downspouts.

Think about what you just built. You took a downspout that carried water 8 feet into the yard and replaced its discharge point with a plastic barrel against your block wall. Every heavy rain, that barrel fills in minutes and then pours out at the top, six inches from your foundation.

We've traced wet basements and settled sidewalks back to exactly that. In spring, when ground around Madison and Janesville is still partly frozen and saturated, water dumped at the wall has nowhere to go but down along the footing.

Route the overflow like you'd route a downspout: at least 6 to 10 feet out, onto ground that slopes away. The same principles in our guide on where downspouts should drain apply here, because during any real storm the barrel overflow is your downspout.

If your yard is flat or pitched toward the house, solve that before you add a barrel.

Give the rain barrel a real base

A full 55-gallon barrel weighs about 460 pounds. Set that on grass and it will sink, tilt and eventually tip, which is genuinely dangerous around kids and pets.

Build a base from solid concrete blocks or a small pad, level it, and give the barrel 12 to 18 inches of lift. Gravity is your only pump, and that lift is what makes the spigot usable at all.

Not sure your gutters and downspouts are moving water away from the house in the first place? That's the part worth checking before you add anything. We'll look at gutter sizing, pitch, seams and discharge points and tell you straight. Free, no pressure. Call (608) 909-9109.

Is the water safe? Roofs, edibles and what not to do with it

Start here: harvested roof water is not potable. Don't drink it, don't cook with it, don't fill the dog's bowl. It runs across a surface that collects bird droppings, pollen, dust, road grit and whatever the squirrels left behind.

For the garden it's fine, with a little care. Water at the soil line instead of spraying foliage, especially on lettuce, spinach, herbs and anything else you eat raw. Established tomatoes, beans, squash and ornamentals do great on it. Ease off overhead watering on leafy greens in the week or two before harvest, and wash your produce like you would anyway. Seedlings and sprouts are the one spot we'd just use tap water.

Your roof covering matters too. Asphalt shingles are the most common source here and the runoff carries granule grit and trace metals, which is why the soil-watering rule exists. If you have zinc or copper strips installed up at the ridge for moss and algae control, or you've had a roof wash or moss treatment done recently, skip collecting for a few good rains and keep that water off edibles. Treated wood shakes are the one roof we'd never harvest from for a food garden. Painted metal roofs generally give the cleanest water of the bunch.

Mosquitoes, algae and gutter guards

Mosquitoes need standing water for about a week to breed. Screen the inlet and the overflow port with fine mesh, keep the lid latched, and drop in a Bti mosquito dunk, a bacteria that kills larvae and is considered safe around pets, kids and vegetable beds. Then use the water. A barrel you draw down weekly never becomes a nursery.

For algae, buy a dark, opaque barrel. Clear, translucent and white barrels grow a green film by mid-July, because sunlight plus roof grit is all algae needs. Water stored more than a few weeks starts to smell, so use it and refill rather than hoarding it.

Gutter guards help. Leaf screens keep twigs, shingle grit and seed pods out of the downspout, so barrel water stays cleaner and the inlet screen clogs less. Guards don't interfere with a diverter install at all. If you have heavy tree cover and no guards, a first-flush diverter earns its keep by dumping the first few dirty gallons before collection starts.

One thing to watch while you're cleaning that inlet screen: if you're scooping a visible layer of shingle granules out of the barrel every time, or you can see bare black patches on the shingles from the driveway, that's an aging roof rather than a barrel problem. Worth having someone look at the roof surface itself, especially after a hail season.

Getting the water out (the part people are surprised by)

A rain barrel spigot produces roughly 1-2 psi. Your house hose bib runs 40 psi or better. That gap explains every disappointed rain barrel owner we've talked to.

What that means in practice:

• Watering cans work great. This is what a barrel is really for. Elevate it so a can fits under the spigot.
• A short soaker hose works if it runs downhill from the barrel and isn't more than 25 feet or so. Low pressure and soaker hose are a natural match.
• A standard hose and nozzle will not work. No spray, no sprinkler, no wand. It dribbles.
• A small submersible or transfer pump fixes it if you want real hose pressure. Inexpensive utility pumps handle this fine. Just remember to pull it before you winterize.

Winterizing: not optional in Wisconsin

Water expands when it freezes. A barrel with a few inches left in the bottom cracks at the seam or blows out the spigot after a couple of freeze-thaw cycles, and diverter fittings split the same way, leaving you with a leak dumping water down the side of the house all winter.

Before the first hard freeze, usually late October into November here:

1. Drain the barrel completely, including the spigot and hoses
2. Disconnect the barrel and feed hose from the diverter
3. Set the diverter to its winter bypass position, or cap the port
4. Reinstall the lower downspout section and the extension
5. Store the barrel upside down or indoors

Step 4 is the one people skip, and it's the important one. January thaws and February ice dams still send water down your downspouts. If the barrel is gone but the downspout isn't reconnected, you've got water discharging at the wall for four months.

Watch the shoulder season, too. South-central Wisconsin can drop below freezing overnight in early October while gardens are still going. Once the forecast starts showing 28 degrees, run the barrel low and leave it that way: a barrel a third full has room for ice to expand, a full one doesn't. If a cold snap catches you with a full barrel, open the spigot and let it drain overnight, even if you're not done with the season yet.

Rules, rebates, and where a barrel fits in a real gutter plan

Collecting roof runoff outdoors for garden use is legal in Wisconsin. Anything plumbed into the house for indoor use falls under the state plumbing code and is a licensed-plumber project. The likelier snag is private: check HOA covenants or historic-district guidelines before putting a barrel on a street-facing wall.

On rebates, Madison and some other Dane County municipalities have run discounted rain barrel sales through stormwater programs in past years, and utilities elsewhere in the state have done similar. Availability and pricing change year to year, so confirm with your own city, village or county public works or stormwater office before you count on it.

Here's the honest framing: a rain barrel is a nice addition on top of a gutter system that already works. It's not a fix for one that doesn't. If your gutters overflow in heavy rain, sag between hangers, leak at the seams, or dump water at the corner of the house, a barrel just adds another failure point. Our gutter installation and repair services handle that side of it: correctly sized seamless gutters, enough downspouts for the roof area, and discharge points that genuinely move water away from the foundation.

Want a second set of eyes before you buy a barrel?

We're a licensed and insured, locally owned exterior contractor that's been working in this area since 1979, running seamless gutter and downspout work alongside roofing and siding across Dane, Rock and Green counties, Sun Prairie, Middleton, Verona, Stoughton, Janesville and Monroe. You can read what neighbors say about us in our customer reviews.

Call (608) 909-9109 or reach out here and we'll look at your gutters and downspouts. We'll tell you whether the system is handling the volume, where your water is actually going, and whether a rain barrel makes sense on your house. If everything checks out, we'll say so and leave. If something needs work, you get a clear written estimate and time to think about it.

The inspection is free. It costs nothing to find out, and finding out in July is a lot cheaper than finding out in March.