Water heater: repair or replace? The phone-triage questions that get it right before the truck rolls

A guy in Hyattsville calls at 8am: no hot water, water heater's making a knocking sound, probably just the igniter. Fifteen-minute fix, easy morning call. Your tech shows up with an igniter kit in the truck bag — and the tank's weeping rust down the side of the jacket, twelve years old, the bottom seam is what's actually failing. Wrong parts, wrong visit, and now you're either driving back to the shop or apologizing to the next customer on today's route because this one just turned into a two-hour install nobody scheduled for.

That's not a bad tech. That's a bad intake. The fifteen-minute fix and the four-hour replacement sound almost identical over the phone — both start with "no hot water" — and whoever answers has maybe ninety seconds to tell them apart before a truck commits to one or the other.

Here's what actually separates them, in the order that matters on the call.

Before any of that: the filter that runs first

The unit in that story is a gas water heater — igniter, pilot, a burner with a gas valve on it — and everything below asks a homeowner to go stand in front of it and describe what they see. So two questions come before the triage, and they aren't triage questions. They don't feed the repair-or-replace decision at all. They decide whether this is still a plumbing call.

Do you smell gas, or hear hissing? If yes, it stops being your call right there. Washington Gas is explicit about the shape of the answer: leave the area, don't turn anything electrical on or off, don't operate anything that could spark, and don't use a phone inside the building — call 911 and the utility's emergency line from outside, away from the leak. Which means what you say is get everyone out and hang up on me, then dial from the sidewalk. Not "check the valve first." Not "see if the pilot's out." Nobody relights anything and nobody goes back in until the utility says the area is safe.

Is a CO alarm sounding, or does anyone in the house have a headache, dizziness, or nausea? A gas water heater that isn't venting properly puts combustion products into the room instead of up the flue, and the symptoms read like the flu. CPSC says don't go hunting for the source: get outside to fresh air, call 911, and don't go back in until responders say you can. After that it's a job for whoever handles gas venting, before it's ever a repair-or-replace question.

Both of those are categorical. It doesn't matter how faint the smell is, how old the tank is, or how certain the caller sounds that it's nothing. If either answer is yes, everything below this line stops — you don't get the age, you don't get the leak location, and you don't need them, because that truck isn't rolling to a parts decision. Same rule as a sewage backup: no judgment call.

And one limit that governs the whole rest of the script rather than being a question: nobody relights a pilot, resets a cutoff, or opens a gas control over the phone. Every question below asks a caller to look and describe. Not one of them asks a caller to touch.

Question one: how old is the tank

This is the single most useful thing you can get out of someone who's standing in front of their water heater reading a rusty sticker. A tank inside its expected working life is worth repairing almost every time — a thermocouple, an igniter, a bad thermostat, a leaking drain valve are all real fixes on a unit that has years left. A tank well past it is a different conversation, because the part that's failing next probably isn't a part at all.

ENERGY STAR — the joint EPA/DOE program, not a plumbing blog — puts it plainly: "if you suspect your water heater is more than 10 years old — it is time to consider replacing it before you're left with an emergency decision." That's not a hard cutoff, it's a signal to ask the next question harder. A 6-year-old tank with a bad thermocouple is a repair call. A 14-year-old tank with the same symptom deserves a replacement quote, not just a part swap, because the next failure on that unit is a real possibility inside the same service call.

Question two: where's the water actually coming from

This is the question that ends most repair-vs-replace arguments outright, and it's a question your intake person can ask without seeing the unit.

Water beading at a threaded connection — a fitting, a union, the cold-water inlet, the drain valve — is a repair. Those are mechanical joints; they come apart, they get resealed, the tank is fine. So ask for three things, not two: is it coming from a threaded joint, from the tank body itself (the steel jacket, low on the side, sometimes rust-colored), or is the temperature-and-pressure (T&P) relief valve actually discharging?

That third bucket sits in the repair pile on most intake scripts. It does not belong there. A T&P valve that is discharging is a symptom to diagnose, never a wear item to swap. A.O. Smith's Technical Bulletin #52, the manufacturer reference written for this exact symptom, splits it two ways. A slow intermittent weep or dribble is the valve relieving on pressure — commonly thermal expansion in a closed system, a real thing to fix and not the valve's fault. A large volume of hot water discharging sporadically is the valve relieving on temperature, and the bulletin leaves no room on what that means: "The only cause of this problem is a malfunctioning thermostat."

Sit with what that implies while somebody's on the phone with you. The valve isn't broken. The valve is the one part of that appliance still doing its job — dumping water because the control that was supposed to shut the burner off didn't. Replace it and you have taken the last safety device off a tank that is actively overheating. So the intake answer isn't a part number. It's a tech, and a diagnosis of the control, and in the meantime nobody stands near the discharge pipe, because what comes out of it is hot enough to scald.

Water weeping from the tank body is not a repair call either, full stop. Once the inner tank has corroded through, there's no patch, no seal, no part number that fixes it — the tank gets replaced, not repaired.

And that bucket is wider than most scripts draw it. Bulletin #52 again, on the spud — the fitting welded into the tank shell where the pipe threads in: "Spuds are welded to the tank and are not repairable. The heater should be replaced." So "it's leaking right where the pipe goes into the tank" is not automatically a threaded-joint repair. Nobody tells a seeping spud from a weeping thread over the phone, which is the point: that one gets scheduled as a diagnosis, not as a parts swap. Threaded joint versus tank body is still worth more than every other diagnostic question on this list combined for deciding which truck configuration to send — you just can't always settle it on the call, and the honest move when you can't is to say so.

Question three: what's it actually doing

"No hot water" can mean the burner won't light, the water's lukewarm, or the tank is making a popping or rumbling sound that wasn't there before. A dead pilot is a repair — a thermocouple, an igniter, a real part with a real number on it.

A tripped high-limit is not the same animal, and bracketing the two is how a dangerous call gets scheduled like a cheap one. The high-limit — the ECO, the over-temperature cutoff wired into the control — only fires after the water has already gone past where it was ever supposed to be. It's the second line of defense, behind the thermostat. It tripping means the first line failed. That's the same story as a T&P valve discharging one section up, and it earns the same answer: diagnose the control, don't just clear the cutoff and leave. A high-limit that's been reset once and tripped again isn't a stubborn switch — it's a tank that keeps overheating, and it goes on the schedule as exactly that.

A tank that's been rumbling for months and finally quit is often sediment that's built up enough to insulate the burner from the water above it — still sometimes a repair (a flush, occasionally a new heating element or burner assembly), but it's the point where "how old is it" and "where's the water" both need a second look, because a heavily scaled tank that old is closer to the end of its working life than a clean one.

The DMV-specific factor worth asking about

Water hardness genuinely varies across this region by utility, and it's a real, verifiable reason a tank in one county scales up faster than an identical tank a county over. DC Water puts its own supply at roughly 70–120 ppm, 3–9 grains per gallon — moderately hard, with the number drifting higher in summer. Prince William Water, further out in the Virginia suburbs, reports several of its systems at 7.0–10.5 grains per gallon, which crosses into its own "hard" classification — not a different planet from DC's number, but consistently higher. Fairfax Water's own FAQ states a range of 5–10 grains per gallon (84–170 mg/L) for its service area, spanning both categories depending on where in the system a customer sits.

None of that tells you a specific unit's lifespan — don't let anyone on the phone claim it does. What it tells you is that "how's your water, ever notice scale on your fixtures or a lot of white buildup on the shower head" is a legitimate triage question in this region in a way it wouldn't be in a market with uniformly soft water, and it's worth asking alongside the age question rather than instead of it.

The permit question, briefly

A straight repair — thermocouple, igniter, drain valve, a T&P valve replaced once the control's been diagnosed — doesn't typically trigger a permit anywhere in the DMV. A full replacement, especially anything touching gas line, venting, or moving the unit's location, often does, and the specific trigger varies by jurisdiction. We laid out what actually requires a permit across DC, WSSC's territory, and Fairfax County separately — including the one that trips people up by name alone: Fairfax Water is the utility, but the plumbing permit comes from Fairfax County's Land Development Services, not the water company. Check that breakdown rather than guessing on the call, and when in doubt, check your own county's requirement directly before promising a customer either way.

Where this fits into what Dialkeep actually does

Disclosed pitch, one section, flagged as a pitch — and the disclosure that matters most goes first: Dialkeep isn't live yet. Nobody's shop is running this script on real calls today, and there's no number for you to dial tonight and judge it.

What it's designed to do when it launches is exactly this script: the gas and CO filter before anything else, then age of the unit, symptom, leak location, tank body versus threaded joint, in that order, the same way at 8am as at 8pm. And quote the service-call fee you've configured accurately if the caller asks, without improvising a number. (On the demo persona that figure is $89. That's the demo shop's configured price, not a Dialkeep price — on your line it's whatever you set.) That's genuinely useful, because a truck that rolls with the right parts based on good triage questions is worth more than a truck that rolls fast with the wrong ones.

Now the part that isn't useful, stated flatly. It doesn't schedule anything. It doesn't send you a message of any kind. It doesn't put a ticket in front of your dispatcher. Not automatically, and not by some slower manual route either — none of what the caller says reaches you at all. What's real is the caller's half of the ninety seconds: they get asked the right questions and get a straight answer instead of a beep. Your half — finding out what was said, deciding the truck, getting it scheduled — is untouched, because that bridge hasn't shipped.

The rest of it

If you want the wider math on what a missed or mishandled call costs a one-truck shop, or you're weighing Dialkeep against a live answering service on price, the DMV solo plumber's guide to answering services walks through the options with real numbers. For another intake script built the same way — safety first, then the questions that actually decide the call — see how to triage a sump pump failure call. And the fuller rundown of what's built, what's priced, and what's still roadmap lives on the plumbing page.