The Homebuyer’s Plumbing Checklist: What to Inspect Before Closing on a New House

A home can look perfect during a showing and still have plumbing problems that do not show up until after you move in.

That is not because anyone hid them. Most general plumbing issues are behind walls, underground, or inside systems that look fine from the outside. A general home inspection covers the basics, but plumbing is one of the areas where the basics are not always enough.

No one wants to face a big plumbing repair just months after moving in. Still, most buyers only check if the water runs and the toilet flushes, unsure what else to look for.

This checklist walks through the plumbing areas worth inspecting closely before you close, so you know what you are buying before it becomes your responsibility.

Why a General Home Inspection May Not Be Enough for Plumbing

A standard home inspection covers a wide range of systems in a limited time, which means plumbing often gets a surface-level check rather than a thorough evaluation.

Inspectors make sure fixtures work, check for visible leaks, and note clear issues like corroded pipes or missing shutoff valves. These steps catch the obvious problems. However, they usually do not check the sewer line with a camera, test water pressure, or look at pipes hidden behind walls.

Now, this is not a fault of the inspection process, just a limit of what can be done in one visit. Inspectors have to check the roof, electrical, HVAC, structure, and plumbing all at once. A plumbing specialist can look more closely at the system that often hides the most costly problems.

The Plumbing Checklist: What to Inspect Before Closing

These are the areas of the plumbing system most likely to hold hidden problems and most expensive to fix after closing.

• Water pressure at multiple fixtures:
  Try turning on a few faucets and showers at once. If the water pressure drops a lot, it could mean there is a pipe blockage, a bad pressure regulator, or pipes that are too small. If only the hot water feels weak, there might be sediment in the pipes or a problem with the water heater.
  
• Visible pipe material:
  Look at any exposed pipes in the basement, crawlspace, or utility room. Galvanised steel pipes can rust inside over time, and slow down water flow. Polybutylene pipes often fail at the joints. Copper and PEX pipes last longer. Knowing the pipe material helps you plan for future repairs or replacements.
  
• Sewer line condition:
  This is the big one. Ask whether a sewer camera inspection has been done. If it has not, request one before closing. The sewer line is one of the most expensive plumbing components to repair or replace, and damage from root intrusion, soil movement, or simple age is completely invisible from inside the house. A camera shows the interior condition and identifies cracks, joint separation, or blockages before they become your responsibility.
  
• Water heater age and condition:
  Find the data plate on the unit and check the date of manufacture. Most tank water heaters last eight to twelve years. A unit near the end of that window is not a dealbreaker, but it is a cost to factor into your budget. Look for corrosion on the fittings, moisture or staining around the base, or rust-coloured hot water. Any of these suggests the unit may need water heater repair or replacement soon after you move in.
  
• Drain performance throughout the house:
  During your walkthrough, run water in every sink, tub, and shower to see how fast they drain. If several drains are slow at once, it could mean a problem in the main line, not just a simple clog. Gurgling sounds or water backing up in one fixture when another is running are signs of a deeper issue.
  
• Signs of past or active leaks:
  Check under each sink, around the base of toilets, and in the basement or crawlspace for water stains, warped wood, mold, or musty smells. Old leaks that were not fixed well can return. If you find any moisture near fixtures, pipes, or on the floor, look into it before closing.
  
• Shutoff valves and supply lines:
  Test the main shutoff valve and individual fixture shutoffs. A valve that is stuck, corroded, or will not close fully is a problem in any future plumbing emergency. Check the supply lines under sinks and behind toilets. Older rubber or plastic lines should be replaced with braided stainless steel, which is the current standard.
  
• Outdoor plumbing and hose bibs:
  Turn on the exterior faucets and check for leaks, drips, or weak flow. In older homes, outdoor plumbing can be connected to supply lines that have corroded or were never properly winterised. These are easy to miss during a showing and easy to forget until the first freeze.

What a Plumber Sees That a Buyer Cannot

You can check everything on this list during your walkthrough. However, some of the most costly plumbing problems need a professional’s tools and experience to spot before they show up.

A plumber can test the whole water system to see how it really performs, not just how one faucet feels. With a sewer camera, they can look inside the pipes and spot cracks, roots, or other hidden problems. They can also check the water heater for issues you cannot see, like sediment or worn-out parts.

Getting a plumbing inspection before you buy costs much less than fixing a sewer line or water heater in your first year. It is one of the easiest ways to know what you are really getting.

Close With Confidence, Not With Surprises

Plumbing is one of the most expensive parts of a home to fix, and it often hides problems until after you have bought the house.

Inspecting it properly before closing is not overcautious. It is how you make sure the home you are buying is the home you think you are buying.

At Rockwater Plumbing, we can inspect the plumbing system before you close, checking water pressure, the sewer line, the water heater, and the condition of the pipes. 

If you are buying a home and want a clear look at the plumbing before you commit, schedule an inspection with us, and we will give you straightforward answers.