This guide highlights the five plumbing defects that inspectors most often find in new construction.
When you walk through a brand-new home, everything looks spotless. Shiny fixtures, clean lines, and no signs of wear. But behind the walls and beneath the floors, plumbing systems are not always as flawless as they appear.
New construction homes can hide plumbing defects that only show up later: after you’ve moved in. From slow leaks to poor installation practices, these problems may cause water damage, higher utility bills, or even health concerns.
1. Leaks at Fixtures and Connections
Leaks are one of the most common defects inspectors find in brand-new homes. While you might expect leaks in older houses, they can just as easily appear in new builds.
Leaks often happen because:
- Pipes or fittings were not tightened properly
- Sealants like plumber’s tape or caulk were skipped or applied poorly
- Cheap or defective fixtures were installed
Even a slow drip can cause significant problems if it goes unnoticed. Cabinet bottoms can swell, drywall can soften, and flooring can warp. If water pools long enough, mold may begin to grow, creating air quality issues and requiring costly remediation.
The EPA estimates that household leaks waste nearly 1 trillion gallons of water nationwide every year.
Catching leaks at the inspection stage can prevent your brand-new home from becoming part of that statistic.
Inspectors check sinks, toilets, showers, and water supply lines for dampness, staining, and dripping valves. Identifying leaks before you move in means they can be corrected by the builder, saving you time and frustration later.
2. Poorly Sloped Drain Lines
Drain lines must be installed at a specific slope to allow wastewater to move out of the home efficiently. If the slope is too shallow, water sits in the pipe and collects debris. If it’s too steep, water flows too quickly and leaves solids behind.
Both scenarios lead to the same problem: slow drains and frequent clogs.
Improper slope is a common construction error, especially when plumbing is installed quickly or without careful measurement.
The issue may not be obvious during a walkthrough because drains appear to work at first. Problems typically show up after a few weeks or months of use, once buildup starts inside the pipes.
Why it matters:
- Wastewater backups can occur in sinks, tubs, or showers
- Trapped water and debris create unpleasant odors
- Long-term fixes may require removing flooring or walls to replace pipes
Inspectors test drainage throughout the home to make sure pipes are sloped correctly. This simple step can save you from expensive plumbing work down the line.
3. Incomplete or Improperly Installed Venting
Venting is one of the most overlooked parts of a plumbing system. Vent pipes let air into the system so wastewater flows freely and gases escape safely through the roof.
Without proper venting, water drains slowly, toilets gurgle, and sewer odors may enter the home.
Defects inspectors often find include:
- Missing vent pipes for individual fixtures
- Vents that are routed incorrectly or never connected to the main stack
- Vent pipes that were capped or blocked during construction
Poor venting is not just an annoyance. It can lead to repeated clogs, unsanitary conditions, and even health risks from sewer gas exposure.
A professional inspection ensures vents are present, properly connected, and unobstructed. Inspectors also check for signs of “air admittance valves” used inappropriately as shortcuts during construction, since these can fail and cause long-term issues.
4. Risky Cross-Connections
A cross-connection happens when drinking water lines are connected in a way that allows contamination from wastewater or other sources. Without backflow prevention, dirty water can flow into the clean water supply.
This is a serious safety concern. Contaminated water may carry bacteria, chemicals, or pesticides that can make people sick. Appliances like dishwashers, washing machines, and irrigation tie-ins are common areas where cross-connections occur.
Most municipalities require backflow prevention devices, but new construction inspections often reveal missing or improperly installed components.
Inspectors check for cross-connections and test backflow devices to ensure the water supply is safe. Correcting these problems before move-in is critical, since cross-contamination may not be obvious until it becomes a health hazard.
5. Incorrectly Installed Water Heaters
Water heaters are essential to modern living, but in new construction homes, they are not always installed properly. Defects may include:
- Missing or improperly installed pressure relief valves
- Poor venting of gas water heaters
- Inadequate clearance around the unit
- Incorrect temperature or pressure settings
These issues affect efficiency, shorten the lifespan of the unit, and can create fire or explosion risks in extreme cases.
Home inspectors verify water heater installation against both standards and manufacturer requirements. Your inspector should also ensure the unit is sized properly for the home so that you won’t run out of hot water as soon as you move in.
The Hidden Cost of Overlooking Plumbing Defects
Plumbing is often hidden behind drywall, which makes it easy for problems to go unnoticed until they become major. Unfortunately, plumbing issues are also some of the most expensive to repair.
Examples include:
- Replacing a poorly sloped drain line can cost thousands because walls or floors may need to be opened.
- Mold remediation from a hidden leak can easily exceed the cost of the original defect.
- Replacing a faulty water heater runs from $900 to $1,800, according to HomeAdvisor.
A new construction inspection is your best defense against these costs. Identifying defects before move-in means the builder is responsible for fixing them, not you.
Other Related Questions
Does a standard home inspection cover plumbing in new construction?
Yes, but new construction inspections focus more closely on installation quality. They identify issues that might not be obvious during a basic walkthrough.
Can new homes have other defects besides plumbing?
Yes. Electrical systems, roofing, HVAC, and structural framing can also show problems. InsideOut Inspections Plus provides full new construction inspections that cover all major systems.
What is a sewer scope inspection, and do new homes need one?
A sewer scope uses a camera to check the condition of underground sewer lines. Even brand-new homes can have crushed or poorly installed pipes that cause backups. Adding a sewer scope inspection to your new construction evaluation ensures the plumbing system is safe.
When to Call a Professional
The best time to call a professional is before you move into your new home. Scheduling a new construction inspection protects your investment and helps you avoid costly surprises.
A professional inspector can:
- Catch plumbing defects early, so the builder is responsible for repairs
- Provide documentation that protects you during warranty claims
- Check other major systems so no part of the home is overlooked
- Give you confidence that your new home is move-in ready
InsideOut Inspections Plus serves buyers in Michigan and Ohio with detailed new construction inspections.
Our team looks beyond the surface to ensure plumbing, electrical, HVAC, and structural systems are installed correctly.
Conclusion
Plumbing systems may be hidden from view, but they are too important to ignore. Leaks, poor venting, or cross-connections can all create costly headaches in a brand-new home.
By understanding the plumbing defects that show up most often, you’ll be prepared to ask the right questions, schedule inspections, and make confident decisions.
Reach out to InsideOut Inspections Plus today to schedule your new construction inspection. Our experts will check plumbing and every other major system so you can move in with peace of mind.
