Tankless water heaters: casing leaks versus connection leaks

I hear you on those sneaky connection leaks. The worst part is, by the time you spot the damage, it’s like the water’s been throwing a secret party in your wall for months. I had a “fun” surprise with my bathroom vanity - thought I was being all eco-conscious with my reclaimed wood, but turns out, it’s not a fan of slow drips. Swelled up like a sponge cake gone wrong.

I do wonder, though - has anyone tried those smart leak detectors? I keep seeing ads for them, but I’m half convinced they’re just going to ping my phone every time I spill my coffee. Still, if it saves me from another round of moldy baseboards, maybe it’s worth the paranoia... Anyone found them actually helpful, or are they just another gadget collecting dust?

I’ve actually installed a couple of those smart leak detectors for clients - mixed results, honestly. They’re great if you’ve got spots that are hard to check regularly, like under old sinks or behind appliances. You do get the odd false alarm (pet water bowl spill set one off once), but it’s better than finding out months later with a warped floor. Curious if anyone’s had luck with the ones that shut off the water automatically? That seems like it could be a game-changer, but I wonder how reliable they are in practice...

You do get the odd false alarm (pet water bowl spill set one off once), but it’s better than finding out months later with a warped floor. Curious if anyone’s had luck with the ones that shut o...

Had a small leak under the dishwasher last year - didn’t notice until the laminate started bubbling. Wish I’d had one of those detectors then, even with the false alarms. About the auto shut-off ones, I’ve looked into them but the price tag’s a bit much for me. I keep thinking, what if it shuts off the water over a tiny spill and I’m stuck with no water while I’m at work? Seems like a hassle, but maybe I’m just being cheap...

Honestly, I get where you’re coming from. Those auto shut-off valves are a bit of an investment, and yeah, they can be a pain if you get a false trigger. I’ve seen a few folks get locked out of water for hours over a tipped mop bucket or a leaky dog bowl. But on the flip side, I’ve also seen what happens when a slow leak goes unnoticed for weeks - warped floors, mold, cabinets ruined. That’s a much bigger headache and way more expensive to fix.

If you’re worried about the system shutting off over something minor, some of the newer models let you adjust the sensitivity or even send you an alert before shutting off. Not perfect, but it helps. And honestly, even the “cheap” detectors that just beep are better than nothing. I’ve got one under my own sink at home - caught a tiny drip before it turned into a disaster.

You’re not being cheap, just practical. Not everyone needs the full smart-home setup. But if you’ve already had one leak sneak up on you, even a basic detector is worth it. The peace of mind is huge, especially if you’re out all day. And hey, if you ever do go for the auto shut-off, just make sure to test it with a cup of water first - saves a lot of surprises down the line.

Leaks at the connections have always been the bigger problem in my experience. A slow drip from the box is annoying, sure, but a loose or failing connection can dump gallons before you know it - especially if it goes unnoticed over a weekend. I had a tenant once who thought a little moisture under the sink was “just condensation.” By the time I got there, the cabinet was trashed and the floor was buckling. Detectors are cheap insurance compared to that mess. I’d rather deal with a false alarm than a major repair bill.

Couldn’t agree more - connection leaks are the real silent killers. Drips from the box might annoy you, but a blown supply line or loose fitting can wreck an entire kitchen overnight. People always underestimate how fast water damage spreads. I’ve seen warped floors, mold, you name it. Honestly, most “condensation” under a sink isn’t just condensation... it’s the start of a headache. Those cheap leak detectors are worth their weight in gold compared to ripping out cabinets.

I’ve seen warped floors, mold, you name it.

I get where you’re coming from, but I’d argue that “drips from the box” can be just as insidious, especially if they go unnoticed behind cabinetry. A slow drip over weeks can rot particle board and attract pests before anyone even realizes there’s a problem. Quick catastrophic leaks are dramatic, sure, but the long-term damage from a persistent drip shouldn’t be underestimated. Those leak detectors are great, but regular visual checks under the sink still catch things tech might miss.

Drips from the box are sneaky for sure, but I’d say it’s the slow leaks at connections that really get under my skin. Those tiny, almost invisible leaks can go on for ages, especially if they’re tucked behind a garbage disposal or wedged in a corner where nobody ever looks. I’ve pulled out cabinets before and found the whole back side just crumbling apart, and you’d never know unless you were looking for it.

One thing I’ve noticed is that people tend to trust those leak detectors a bit too much. They’re awesome when they work, but if the sensor isn’t right where the water pools - or if it gets knocked out of place - you’re back to square one. I’ve seen a few setups where the detector was sitting on top of a pipe instead of underneath, which kind of defeats the purpose.

Visual checks are underrated. I always tell folks to just run their hand along the pipes every now and then. If you feel any dampness or see a little corrosion on fittings, that’s usually your first sign. And don’t forget about those flex hoses - sometimes they’ll look fine but have a pinhole leak spraying a mist that never quite drips down to where you’d notice.

Funny thing, I once found a slow drip that had been feeding a colony of ants for who knows how long. The homeowner thought they just had a pest problem... turns out it was plumbing all along.

I guess what I’m saying is, both types of leaks can do serious damage, but the ones you don’t see are usually the worst. Catastrophic leaks make themselves known fast, but the slow creepers? They’re like silent assassins for your cabinets and floors.

Drips from the box and those sneaky connection leaks both have their own brand of misery, but I’m with you - slow leaks at the joints or behind appliances are way more insidious. I’ve seen particleboard cabinets just dissolve into mush over time because of a pinhole leak nobody could spot without pulling everything apart.

One thing I’d tack on - don’t just rely on your hands or eyes. Sometimes, a quick paper towel swipe under connections can reveal moisture you’d never feel otherwise. If the towel comes up damp, you know you’ve got a problem. And when it comes to flex hoses, I always recommend replacing them every 5-7 years, even if they “look fine.” Had a client who learned that the hard way after a braided hose burst while they were on vacation... not pretty.

About those leak detectors: totally agree, they’re only as good as their placement. I’ve found that putting a thin baking sheet under the sink and placing the sensor on that can help catch pooling water faster, especially if your cabinet floor isn’t perfectly level.

At the end of the day, it’s all about catching things early. A little vigilance goes a long way toward avoiding cabinet carnage.

Had a job last year where a slow leak behind the dishwasher went unnoticed for months. By the time anyone realized, the subfloor was black with mold and the whole kitchen had to be torn up. Drips from the box are annoying, but those hidden leaks are just brutal. I always tell folks - if you smell musty odors, don’t ignore it. That’s usually the first sign before you see any water.

Yeah, hidden leaks are way worse in my book. At least with a drip you usually notice it before things get out of hand. I’m always paranoid about musty smells now - learned that lesson the hard way with a bathroom sink. Mold cleanup isn’t cheap.

Honestly, I’m with you - hidden leaks are a real headache. At least a steady drip under the sink is obvious and you can get to it before things spiral. But sometimes, I wonder if folks overlook how even a small, slow drip can rot out a cabinet base over time, especially if you’ve got particle board. I had to replace a vanity once because of that exact thing... not as dramatic as mold in the walls, but still a pain and not cheap. Either way, water’s sneaky - gotta stay vigilant or it’ll get you one way or another.

Drips are like that one ant you spot in your kitchen - ignore it, and suddenly you’ve got a whole colony. Here’s my step-by-step: 1) Stick a dry paper towel under your pipes and check it every few days. 2) If it’s damp, tighten those connections or swap out the washer. 3) For eco points, catch leaks in a bucket and use the water for plants. I learned the hard way that even a “tiny” drip can warp particle board faster than you’d think... and there’s nothing green about tossing a whole cabinet in the landfill.

Leaks at the connections usually get my attention faster than a drip from the box. Connections can go from a slow drip to a full-on spray if the fitting gives out. Curious - has anyone had a box leak that turned into something major, or is it mostly just slow damage over time?

I’ve actually seen a box leak escalate beyond the usual slow drip - though it’s not common. Once had a utility room where a tiny crack in the box went unnoticed behind a washer. Over a few months, it turned into a small but steady stream, soaking the drywall and baseboards. By the time anyone realized, there was some pretty serious water damage and a bit of mold.

Connections get most of the attention, and for good reason - they can fail fast if the fitting pops or threads strip. But box leaks can sneak up on you, especially if they're hidden or if the box is set into a wall. It’s usually a slow burn, but if the plastic gets brittle or shifts, it can let loose more water than you’d expect.

Moral of the story: don’t ignore either one. I’d still say connection leaks are the bigger risk for sudden flooding, but box leaks can definitely cause headaches if they go undetected.

That’s actually kind of eye-opening. I always figured the big danger was a connection popping off and flooding everything, but your story about the box leak makes me rethink that. It’s wild how something so small can cause so much damage if it’s hidden away. Makes me want to check behind my washer now... Thanks for sharing - definitely not something I would’ve thought to look for before owning a place.

Honestly, I used to think the same - like, if the hose didn’t burst, I was good. But then I found a slow leak behind my washer that had been feeding a whole ecosystem of mystery mold. Turns out, the tiny drips are sneaky villains. Now I check back there every few months... and try not to gag at whatever’s growing.

- Had the same thing happen under my kitchen sink - tiny drip, huge mess.
- Mold’s a pain, but water damage is what really gets me.
- I switched to those braided steel hoses and added a leak detector. Not perfect, but it helps.
- Curious - do you think leaks at the valve are worse than at the hose? I always worry about the shutoff failing when I’m away...

Curious - do you think leaks at the valve are worse than at the hose? I always worry about the shutoff failing when I’m away...

Honestly, a valve leak can be a bigger headache long-term. If the shutoff fails, you’re looking at continuous water flow until someone notices - way more potential for damage than a slow hose drip. But hoses tend to give warning signs (bulging, rust), while valves just go. Ever had a supply valve seize up or snap off when you tried to close it? That’s a mess on its own. Wondering if anyone here actually replaces their shutoffs as routine maintenance, or just waits for trouble?

I actually just went through this with my laundry room. The valve looked fine from the outside, but when I tried to shut it off for a washer replacement, it wouldn’t budge - then started dripping around the stem. Ended up calling a plumber because I didn’t want to risk snapping it off. I get why people wait, but after that, I’m leaning toward swapping out the old shutoffs before they become a problem. Hoses at least give you some warning, but valves seem to fail all at once... not a fun surprise.