Something has gone wrong with the water. Start by working out what.

On the gas range the number is first hour delivery; on the electric range it is the tank. Getting that backwards is how two quotes stop being comparable.

Brand is the first thing people shop for and close to the last thing that matters. The major names here sell the same six or seven kinds of system as each other — so the badge cannot make the decision that is actually in front of you.

Most people meet this brand at the quote stage, where a single line reads Dux Ecosmart and sounds like a product. It is a family name that spans a heat pump and two different solar systems — three installations with three different sets of site requirements.

It is the valve that is supposed to let water out. Understanding that one fact sorts out most arguments about a hot water system that leaves a wet patch on the ground.

Every installer recommends the type they fit. The honest version is that your house decides most of it — gas connection, outdoor space, roof aspect and how many showers run at once.

Two showers at once is the question that separates the two types, and the answer is a number the brochure quotes optimistically. Here is what that number means, and what changes if you are on bottled LPG.

The efficiency claim is real, and it is not the interesting part. What sinks a heat pump installation is almost always physical — where the compressor noise lands, how much air it can draw, and what happens on a 2 °C morning.

The word promises hot water the moment you open the tap. What it actually means is that nothing is stored — which fixes one problem completely and introduces a different one that nobody mentions until the second shower goes weak.

Choosing Rheem narrows almost nothing — the range covers gas, electric, heat pump and solar. The useful questions are which one is on your wall, and whether it is repairable.

Most people arrive at this brand through the word Infinity and assume it means one product. It is a family name inside a range that also includes heat pumps, solar and storage tanks — so picking Rinnai still leaves the real decision unmade.

The collectors on the roof are the part you can see. The part that determines whether the system saves you anything is the booster in the tank, and the mode it is left in.

Every sizing chart starts with "how many people". That is the wrong question, and it is why a household of three can run out while a household of five never does. What decides it is your busiest twenty minutes.

A hot water system that leaks is not automatically a hot water system that needs replacing. Where the water is coming from tells you whether this is a valve, a fitting or the end of the tank.

If the cold water is fine and the hot is a trickle, the problem is not your mains pressure. That single observation rules out half the possible causes before anyone opens a toolbox.

A system that produces warm water is still working. Something is either not taking it all the way up, or blending it back down before it reaches you — and which of those it is decides who you need to call.

If the kitchen tap runs hot and the shower does not, your hot water system is working. The fault is in the last two metres of pipe, and that changes both the diagnosis and who you need to call.

The cause is usually one of six things, and which six depends on whether your system is electric, gas or a heat pump. Two of them you can check in five minutes without tools.

The relief valve is the one part of a hot water system designed to let water out. That makes "is it leaking?" the wrong question. The right one is when it discharges, and for how long.

Rusty or brown water is not a plumbing mystery — it is an iron problem, and the only real question is where the iron is coming from. Run the cold tap first and you have narrowed it to one of two answers.

The smell is hydrogen sulphide, and in a storage system it almost always comes from the tank rather than the water supply. One test tells you which one you have.

A storage tank rarely dies of old age. It dies because a part designed to be replaced was never replaced, and nobody told the owner it existed.

It is the smallest part on a hot water installation and the one that explains the strangest symptom in the house — a bathroom that runs lukewarm while the kitchen is scalding.

Stored temperature and delivered temperature are two different things, set by two different parts. Almost every piece of bad advice about hot water starts by confusing them.

A warranty document is a set of conditions, not a promise. Most of what voids one is either never installed correctly in the first place, or never checked afterwards.

Where the water comes from tells you the part. Getting that right is the difference between a five-minute job and fitting three washers into a tap that will keep dripping.

Before anything else, find out whether the blockage is in the pan or further down the line. Plunging a main-line blockage does not clear it — it pushes sewage back through the lowest fixture in the house.

The most useful test in drainage is free: run water at several fixtures and watch what else reacts. It tells you how far down the blockage is before anyone puts a camera in.

If your main line blocks around the same time each year, you almost certainly have roots. Clearing them is maintenance, not a repair — and knowing the difference is what stops the annual bill.

Before anyone opens a wall or quotes for leak detection, your meter will tell you free whether you have a leak at all — and roughly whose it is.

Most tanks are sized by the gap beside the house. The honest order is roof area first, then what you intend to use it for, and only then what fits.

There is no answer to this question that applies to every tank. There is an answer for your tank, and it comes from a laboratory, not from a website.

Most home repair content online is written for the US or the UK, where this line sits somewhere else entirely. In Australia it is drawn tightly, and it is drawn by your state — not nationally.