green plumbing showdown: greywater recycling vs rainwater harvesting

I get the appeal of rainwater, but honestly, I’ve had fewer headaches with greywater once I switched to plant-based soaps and kept a filter on the line. The trick is regular maintenance - if you slack off, yeah, things get gross fast. Rainwater’s great, but in dry spells it’s not always reliable.

Honestly, I’ve seen more folks call me in a panic over greywater backups than rainwater tanks. Sure, maintenance is key, but one missed filter change and you’re ankle-deep in mystery sludge. Rainwater’s not perfect, but at least it doesn’t smell like last week’s shampoo... most of the time.

I get where you’re coming from - greywater systems can turn into a headache if the filters or diverters get neglected. But I’ve seen rainwater tanks cause their own brand of chaos, especially when folks forget about first-flush diverters or let leaf guards clog up. Had a call last winter where a tank overflowed and basically turned the backyard into a swamp because the overflow pipe was blocked with gunk.

Honestly, both setups need regular check-ins. With greywater, yeah, you’re dealing with soap residue and lint, but if you set up an easy-access filter and stick to a monthly rinse-out schedule, it’s not that bad. Rainwater’s less smelly, sure, but if you don’t keep up with mosquito screens and sediment traps, you’ll end up with a tank full of green soup.

Neither system is “set and forget.” If anything, I’d say greywater’s just more honest about what happens when you skip maintenance - it lets you know right away. Rainwater just waits until you need it most before it throws a curveball.

You nailed it - maintenance is the real deal-breaker for both. I’ve had a rainwater tank go green on me after just a couple months of neglect, and it’s not fun cleaning that out. I do think greywater gets a bad rap, but you’re right, it’s at least upfront about issues. Either way, a little routine goes a long way.

Either way, a little routine goes a long way.

Couldn’t agree more. I used to dread the idea of regular upkeep, but honestly, once I got into the habit, it wasn’t nearly as bad as I thought. The rainwater tank gets a quick check every couple weeks now - nothing fancy, just making sure there’s no gunk building up. Greywater’s a bit more hands-on, but at least you know what you’re dealing with. It’s all about finding that balance between effort and payoff, especially when you’re trying to keep costs down.

Routine really does make all the difference. I used to think greywater systems would be a nightmare to keep up, but after a few months, it’s just another part of the weekend chores. Rainwater tanks are definitely lower maintenance, though - sometimes I wish everything was as simple as just checking for leaves and sludge. Still, there’s something satisfying about knowing exactly where your water’s coming from and how it’s being reused. Even if it means getting your hands a little dirty now and then...

I get what you mean about the satisfaction, but I’m always a bit wary with greywater. The maintenance isn’t too bad once you’re in the groove, but I still double-check filters and pipes for any leaks or weird smells. Rainwater tanks feel safer to me, especially with kids around - less chance of cross-contamination if something goes wrong. Still, both save money long-term, just gotta stay on top of the upkeep.

I hear you on the safety thing - rainwater feels a bit more straightforward, especially if you’ve got kids running around. Greywater always makes me double-check everything too, just in case. Have you ever had any issues with your rainwater tank, like algae or bugs getting in? I had to add a mesh cover after a few close calls... Wondering if that’s just me or a common thing.

Yeah, mesh covers are pretty much a must, especially if you’re anywhere near trees or have curious critters around. I’ve seen tanks turn into mosquito hotels in no time if you skip that step. Algae’s a pain too - if the tank gets too much sun, it’ll go green fast. I ended up painting mine a darker color and keeping it tucked behind the shed. Not perfect, but it helps. Kids love poking around, so I’m always double-checking the lids… never a dull moment.

Honestly, I get the whole mesh cover thing, but I’ve had better luck with those solid snap-on lids. Mesh always seemed to sag or let in tiny bugs anyway. For algae, I tried a floating shade ball setup - looks weird but cuts down on sunlight big time. Not sure if it’s for everyone, but it’s worked for me so far.

I get what you mean about mesh covers - tried one on my old rain barrel and it just became a mosquito hotel after a few weeks.

“For algae, I tried a floating shade ball setup - looks weird but cuts down on sunlight big time.”

Rigid covers for rainwater tanks are a bit of a rabbit hole, honestly. Here’s what I’ve seen work (and not work) over the years:

- UV-resistant polycarbonate sheets: These hold up way better than most snap-on lids, especially if you reinforce them with some aluminum angle. Downside is they’re pricier and need decent support across the span or they’ll sag.
- Marine plywood sealed with epoxy: Not the prettiest, but if you seal every edge and hit it with a good exterior paint, it’ll last several seasons. Needs re-coating every couple years though, and can get heavy on bigger tanks.
- Corrugated metal roofing panels: Surprisingly effective if you frame them out right. They reflect heat, don’t warp, and you can hinge them for access. Just watch for sharp edges and rust if you’re in a humid spot.

Snap-on plastic lids almost always warp unless they’re specifically rated for outdoor/UV exposure. Most of the cheap ones are just thin HDPE that goes soft in the sun.

One thing I’ve noticed - no matter what cover you use, if there’s even a tiny gap, mosquitoes will find it. I started using weatherstripping around the rim and that cut down on bugs big time.

Curious - has anyone tried those retractable pool covers on a rain tank? Seems like overkill but maybe there’s a scaled-down version that works for smaller setups. Or maybe I’m just overthinking it...

Also, for anyone doing greywater recycling - are you running into similar algae or mosquito issues, or is that less of a problem since the tanks are usually opaque?

Retractable pool covers on a rain tank - now there’s an idea I hadn’t even considered. I get what you mean about it maybe being overkill, but the convenience factor is tempting. I wonder if you could DIY something similar with those heavy-duty outdoor tarps and a pulley system, instead of springing for a full-on pool cover setup. Has anyone tried something like that, or would the tarp just end up sagging and collecting water on top?

On the greywater side, I’ve been curious about that too. Our greywater barrel is a solid blue plastic, so it doesn’t let in much light, and I haven’t seen any algae yet. But I’m not sure if that’s just luck or if the lack of sunlight really makes that much difference. Does anyone know if the temperature inside those opaque tanks gets high enough to cause other issues, like smells or bacteria? Or is it really just the light that’s the main problem for algae?

Tried the tarp-and-pulley trick over a rain tank once - let’s just say it turned into a backyard waterbed after the first storm. Unless you’ve got a way to keep it taut, you’ll be out there bailing puddles every time it rains.

On greywater: Light’s the main algae culprit, but heat can definitely make things funky. Opaque tanks help, but if your barrel sits in full sun all day, you might notice some smells or even a bit of slime. I’ve found parking mine in the shade keeps things pretty chill... literally and figuratively.

That tarp-and-pulley setup sounds like a classic case of “good in theory, tricky in practice.” I’ve seen a few folks try to rig something similar, and unless you’re using some serious tensioning (think ratchet straps or even a frame), it’s almost impossible to keep the water from pooling. Once that happens, you’re right - might as well call it a kiddie pool. Honestly, sometimes the simplest solution is just a solid, fitted cover.

You nailed it on the greywater too. Light’s the big algae driver, but heat’s no joke either. I’ve had tanks go from fine to funky in a single hot week. Opaque tanks are a must, but even then, if they’re baking in the sun all day, you’ll get that swampy smell creeping in. Shade makes a huge difference. I’ve even seen people build little lean-tos or toss old pallets up for shade - doesn’t have to be fancy.

One thing I’d add: if you’re stuck with a sunny spot, a bit of insulation around the tank can help keep temps down. Nothing high-tech, just some foam board or even old blankets wrapped around the sides. Not perfect, but it slows down the heat gain.

It’s easy to get discouraged when these setups don’t work out right away, but honestly, most of us have had at least one backyard experiment go sideways. Trial and error’s just part of the deal. You’re definitely on the right track thinking about light and heat - those are the big ones for keeping water clean and usable.

I’ve definitely been there with the “good in theory” setups. Tried to rig a rainwater catchment on my shed roof once using a tarp and some bungee cords - looked like a sailboat in a windstorm, and by the next morning, half the water had pooled and stretched the tarp so bad it was basically useless. Ended up just buying a cheap rigid cover and calling it a day. Sometimes you gotta admit defeat and move on.

The insulation trick is a solid one. I’ve wrapped tanks in old moving blankets before, just to see if it’d help, and it actually made a noticeable difference during that brutal July heatwave last year. Still got a bit of that “pond funk” after a while, but it bought me some time before things got gross. I’ve wondered if anyone’s tried burying their tanks a bit, or at least partially - seems like the ground would keep temps steadier, but I’m not sure if that’s more trouble than it’s worth.

One thing I keep running into is figuring out what’s actually safe to use for greywater storage. I know some folks just use whatever barrels they can get their hands on, but I’ve heard stories about certain plastics leaching weird stuff into the water, especially when it gets hot. Anyone ever run into issues with that? I’ve always played it safe with food-grade barrels, but I’m curious if that’s overkill or if it really makes a difference in the long run.

Also, on the algae front - has anyone tried those little aquarium UV sterilizer wands in a bigger tank? I’ve only ever seen them in fish setups, but I keep wondering if they’d scale up for backyard tanks or if that’s just wishful thinking.

Burying tanks is one of those ideas that sounds like a hassle until you actually try it. I helped a friend partially sink a 275-gallon tote a couple summers back - just dug out about half its height and backfilled with gravel for drainage. The difference in temp swings was pretty noticeable, especially during those hot spells. It kept the water cooler and slowed down the algae bloom, but digging that hole was no joke. If you’re dealing with rocky soil or high water tables, it might not be worth the sweat.

On the greywater storage front, I’m firmly in the food-grade camp. There’s a reason certain plastics are rated for potable use - some of those blue barrels people grab from car washes or factories can leach all sorts of stuff when they heat up. I’ve seen barrels warp and get brittle after a season in direct sun, and you end up with weird smells or even oily films on the water. Maybe it’s overkill if you’re just watering trees, but if there’s any chance of splashback onto edibles or pets getting into it, I’d rather not gamble.

As for UV sterilizers, I’ve tinkered with them in larger setups. The little aquarium wands don’t really have enough power to make a dent in anything bigger than a fish tank - they’re designed for slow flow rates and clear water. Scaling up means either running your water through a much beefier inline UV unit (think pool-grade) or just accepting that some algae is inevitable unless you keep things shaded and covered. Honestly, I’ve had better luck just painting tanks black or wrapping them in old billboard vinyl to block sunlight.

Funny how these “simple” green plumbing projects always turn into engineering puzzles... but hey, at least there’s never a dull moment.

Burying tanks really does make a difference with temp swings, no doubt. I’ve seen folks skip the gravel layer and end up with standing water around the tank - never ends well, especially if you get a lot of rain. On the food-grade plastic, I’m with you. I’ve cut open some of those blue barrels after a season and the inside can look pretty sketchy. For UV, unless you’re running a slow trickle and pre-filtering, it’s just not practical for most home setups. Shading or painting tanks is way less hassle in the long run. These projects always seem simple until you’re knee-deep in mud or troubleshooting leaks...

I’ve cut open some of those blue barrels after a season and the inside can look pretty sketchy. For UV, unless you’re running a slow trickle and pre-filtering, it’s just not practical for mos...

I get where you’re coming from on skipping UV, but I’ve actually seen a couple setups where it made a difference - especially if folks are using rainwater for anything beyond irrigation. It’s a pain to maintain, yeah, but sometimes shading or painting just doesn’t cut it if you’re worried about algae or bacteria. That said, I totally agree about the gravel layer. Had a job last year where someone tried to save a few bucks and ended up with a swamp around their tank after the first big storm. Not worth the headache.

sometimes shading or painting just doesn’t cut it if you’re worried about algae or bacteria

Yeah, I’ve noticed that too. Even with dark paint, I still got some funky stuff growing in my barrels after a few months. UV is a hassle, but if you’re using the water for laundry or flushing toilets, it’s probably worth the extra step. On the gravel - totally agree. Skipping proper drainage is just asking for trouble (and mud everywhere). Not fun to fix later.