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When buying or selling a home, people often tend to focus on functionality and aesthetics. While these are important, it can often mean that less attention is given to “what lies beneath”—namely, the plumbing.

Of course, every home will need to go through a plumbing inspection prior to the sale. However, many buyers and sellers know that home inspectors, for the purpose of real estate, generally only perform four tasks when inspecting the plumbing: checking to see that water runs from the taps, drains empty, toilets flush, and there are no visible leaks around pipes and fixtures. That’s because most inspectors simply do not have the technical knowledge necessary to advise buyers if the plumbing in the house is up to code, or even if sewer gas is leaking back into the home.

That’s why today’s savvy homebuyers are having a professional plumbing inspection performed before sealing the deal to ensure they’re not buying a home on the verge of needing costly plumbing services. If a home fails to pass, the buyer will likely want to negotiate a discount to cover any unexpected expenses, or may even back out of the deal—that’s why most sales are contingent on a plumbing inspection report.

So, it’s important for sellers to know how to pass a plumbing inspection—and for buyers to know what to look for.

Professional Plumbing Inspection

Unlike a home inspector, professional plumbing services get into the nitty-gritty details. So what do plumbing inspectors look for? Here are some of the main things they will be checking:

  • Plumbing fixtures, supply lines, and drains
  • Sinks, showers, bathtubs, and toilets
  • Shut-off valves and traps under kitchen, bathroom, and laundry room sinks
  • Bathroom, kitchen, and laundry room draining and venting systems
  • Storage water tanks or tankless water heaters
  • Water filtration systems
  • Shut-off valves
  • Sump pumps

A reputable plumbing service will also use a plumbing video camera to perform an inspection of underground sanitary drains and sewer pipes. They will look for cracks and misalignments, tree root growth in pipes, and blockages that can lead to future drain blockage or even collapse. For homes built before the 1980s, they will also check to be sure Orangeburg piping wasn’t used, as it has now reached the end of its lifespan and will need to be replaced.

How To Pass a Plumbing Inspection

While not all plumbing problems can be easily staved off prior to a plumbing inspection, there are some simple proactive steps sellers can take to improve their chances of passing a professional plumbing inspection. Here are the places where you should focus your plumbing inspection checklist before the professionals come out for a look.


Bathrooms get some pretty heavy traffic in most homes, so predictably this is where many plumbing problems occur.

  • Faucets. Check the sink, bathtub, and shower faucets regularly for leaks, and replace bad washers or cartridges to stop dripping faucets. Also, watch out for weak water pressure or an irregular spray, which could be signs of a calcium buildup on the aerator. You can remove and clean aerators manually, or soak them in vinegar to break up the buildup.
  • Drains. Over time, small soap and hair clogs can turn into full-on drain blockages; before it gets to that point, occasionally disassemble drain traps and remove debris. You can also use a drain snake or high-pressure water jet to clear lines.
  • Toilets. For starters, remove the toilet’s tank lid and observe what happens when you flush; is the toilet continuing to run rather than shutting off at the end of the flush cycle? That wastes a lot of water and could be due to nothing more than a faulty flapper or floater, which is a quick fix. Also, be aware that if your toilet rocks slightly when you sit on it, or if water is seeping around its base, you may need to replace the wax ring that seals the toilet base to the drain opening.
  • Caulking. Compromised caulking allows water from a bathtub or shower to creep behind walls and under floors, leading to major water damage. You should periodically check all caulking and seal any gaps with fresh caulk.


Another room full of plumbing fixtures, the kitchen is another area to concentrate on before the plumbing inspection.

  • Sinks. Kitchen sinks get a lot of abuse, so you should occasionally clean the drain with a mild homemade drain cleaner to keep things flowing. Also, check the sink strainer and P-trap regularly for leaks as water in the sink drains out. The stainer should be replaced if you notice leaks or corrosion, and the P-trap fittings may need to be tightened. For a kitchen sink draining too slowly, you may need to take apart the P-trap or branch drain to remove a clog.
  • Faucets. A leaky kitchen faucet is more than just a nuisance—it can quietly waste hundreds of gallons of water each year. Watch your faucet carefully and make any necessary repairs.
  • Shutoff valves. Water supply to faucets, dishwashers, and refrigerators are controlled by fixture shutoff valves. Periodically, tightly close the valves and be sure they completely shut the water off. If not, they should be replaced.
  • Garbage disposals. Issues with garbage disposals are often discovered in the drain connections where a dishwasher discharge connects to the disposal, or where the disposal discharge runs to the sink drain. If you’re having problems, try tightening the connections at these points or replace the gaskets if they show signs of leakage. Want to learn more? Read our Ultimate Guide to Proper Garbage Disposal Care.
  • Dishwashers. The most common problem with dishwashers is water that won’t drain following the end of the cycle. This can usually be remedied by checking the water discharge hose for clogs or pinching. Also, be sure to check out our blog 5 Reasons Your Dishwasher May Be Clogged and How To Fix It.
  • Refrigerators. If your refrigerator has a water dispenser and icemaker, filters should be changed at least twice a year, and not just to keep water tasting fresh; a clogged filter can block water flow to the dispenser or ice maker. You should also check the water supply hose for signs of wear and replace it if necessary.

Septic and Sewer

Regular inspection and maintenance is the best way to prevent stoppages in the main sewer line or septic system, which can be costly and pose a health risk.

  • Septic systems with a drain field. Most common in rural areas, these need to be pumped out whenever they’re reached capacity. Be sure everyone living in the home knows what they should not put down the drain, and avoid bleach-based cleaners as they can interfere with the biological breakdown of waste which is essential to a septic system. If you notice any foul odors or standing water, this is also a clear sign of seepage that needs to be addressed by a professional to avoid further complications.
  • Sewer mains. If your home is served by a municipal sewer line, you can evaluate how effective it is by filling up, and then emptying at the same time, all sinks and bathtubs. If a floor drains back up or if it takes a long time for all drains to empty, there may be a clog that needs to be snaked.
  • Vent pipes. Usually exiting through the roof, vent pipes equalize air pressure and allow sewer gases to escape. Over time, they can become clogged with debris, compromising their effectiveness. Check periodically to be sure vent pipes are clear of any blockages.


In this catch-all category of your plumbing inspection checklist, we look at a few other areas that should be on your radar.

  • Water heaters. Above the water heater, check for signs of water leakage in the cold water inlet pipe and hot water exit pipe. You’ll also want to look at the base of the water heater to be sure there is no leaking caused by a faulty temperature and pressure relief valve. Also, be sure to watch out for any signs of corrosion, which may require a replacement or risk serious damage.
  • Sump pumps. Located in basements, sump pumps are an under-floor drainage system that should occasionally be checked for proper operation. To do this, manually fill the sump pit with water and make sure the pump activates to empty it.
  • Spigots and sprinklers. Often overlooked, outdoor hose spigots can develop leaks that can often be repaired by replacing washers or cartridges. While you’re at it, check lawn sprinkler systems to make sure all spray heads are operating properly as well. A line crack or loose joint could also allow water to leak even when the irrigation system is off, but finding these leaks can be a little tricky; to spot them, you may need to check your lawn for unusually damp patches or areas of grass that are lusher than their surroundings.
  • Washing machines. If you find rubber hoses that are bulging out, they’ve reached their expiration and need to be replaced to avoid a burst that can cause costly water damage. You should also check the valves that control the hot and cold water hoses; if they don’t completely stop the flow of water when shut off, they’ll need to be replaced.

If you’re selling a home, you probably know it can be a lengthy process and you don’t want to derail a potential deal due to plumbing issues that could have been taken care of in advance, or avoided altogether through proper maintenance. And if you’re buying a home, you want to be sure to get a professional plumbing inspection so that you’re not facing unforeseen expenses and damage down the road. This plumbing inspection checklist serves to give both buyers and sellers an idea of what to look for, and what a professional plumber will look for during an inspection.

If you’re a buyer or a seller in the Sacramento area and need a professional plumbing inspection, you can count on the experts at Express Sewer & Drain. We have the trained eyes you need to spot problems or potential problems that can be corrected to ensure a smooth real estate transaction. Contact us today to set up your professional plumbing inspection.

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