10 Plumbing Mistakes to Avoid For New Home Construction

Allison Woslager • April 11, 2024

A room with wooden walls and pipes in it by royal flush plumbing in tacoma.

Building a new home is an exciting endeavor, but it also comes with its share of challenges, especially when it comes to plumbing. Mistakes in plumbing design and installation can lead to costly repairs and headaches down the road. At Royal Flush Plumbing LLC in Tacoma, we understand the importance of getting your plumbing project right the first time. In this blog, we'll share expert advice on how to avoid ten common plumbing mistakes for new home builds.

1. Improper Ventilation

One of the most common mistakes in new home plumbing is inadequate ventilation. Poorly ventilated plumbing systems can lead to foul odors, slow drainage, and even health hazards due to the buildup of harmful gases. Ensure that your plumbing design includes proper venting for all fixtures to maintain optimal airflow and prevent issues.

2. Incorrect Pipe Sizing

Using incorrect pipe sizes can result in water pressure problems, leaks, and inefficiencies. It’s essential to follow plumbing codes and guidelines when determining the size and type of pipes needed for each fixture and water supply line. For instance, avoid connecting copper pipe to incompatible materials like galvanized metal pipes. Additionally, be cautious of over-tightening black pipe, as it can crack the fitting and cause a potential flood. Consulting with experienced plumbers like Royal Flush Plumbing LLC can help ensure proper pipe sizing and avoid plumbing problems for optimal performance.

3. Neglecting Backflow Prevention

Backflow occurs when contaminated water flows back into the clean water supply, posing serious health risks. Neglecting backflow prevention devices or improper installation can lead to water contamination and regulatory violations. Include backflow prevention measures in your plumbing design and work with certified professionals to install and maintain these devices.

What are the top 3 plumbing issues that can cause a backflow?

Cross-Connections: A cross-connection occurs when a potable water supply line is directly connected to a non-potable source, such as irrigation systems, fire sprinklers, or industrial equipment. If the pressure in the non-potable source exceeds the pressure in the potable water supply, contaminated water can flow backward into the clean water system. Proper backflow prevention devices, such as vacuum breakers and air gaps, are essential to prevent this.
Pressure Changes in the Water Supply: Variations in water pressure, such as those caused by water main breaks, high demand, or pump failures, can lead to backflow conditions. When there is a sudden drop in pressure in the potable water supply, it can create a siphon effect, drawing contaminated water from non-potable sources back into the clean water system. Installing pressure-reducing valves and backflow preventers can mitigate this risk.
Backsiphonage and Backpressure: Backsiphonage occurs when there is a negative pressure in the potable water system, while backpressure occurs when the pressure in a non-potable system exceeds that in the potable system. Backsiphonage can happen due to events like water main breaks or heavy water usage, creating a vacuum that pulls contaminants into the clean water system. Backpressure can result from high-pressure systems such as boilers or elevated tanks forcing contaminants into the potable water supply. Both scenarios require appropriate backflow prevention devices to ensure safe water quality.

To prevent these issues, it is crucial to implement and maintain backflow prevention measures such as check valves, air gaps, and reduced pressure zone (RPZ) assemblies in plumbing systems.

4. Poor Drainage Design

A well-designed drainage system is essential to prevent water backups, flooding, and water damage. Ensuring a properly sloped and sized drain line with the correct fittings such as wyes, tees, and elbows is crucial to avoid issues. Additionally, using a P-trap in plumbing fixtures is important to prevent water siphoning and sewer gas entry. Improper slope, inadequate drain placement, and lack of cleanouts can lead to drainage issues and costly repairs. Avoid treating the kitchen drain as a garbage disposal to prevent build-up issues. Work with experienced plumbers who understand the importance of proper drainage design and implementation.

A plumbing system is being installed in a house under construction by royal flush plumbing in tacoma.

Attempting DIY plumbing work without the necessary skills and knowledge can lead to disastrous results. From improper pipe connections to faulty installations, DIY mistakes can result in leaks, floods, and safety hazards. Using too much drain cleaner, especially in the wrong places, can cause significant damage to pipes and plumbing fixtures. Overuse and misuse of commercial drain cleaners can lead to harsh chemical damage to your plumbing system. Harsh chemicals like drain cleaners can deteriorate pipes over time. It’s advisable to use liquid drain cleaner sparingly and try more natural methods first. Additionally, saddle valves are prone to leaking and are banned in most places as they do not meet current plumbing codes; use Tee fittings or ball valves instead to avoid potential problems and leaks. Avoid overtightening connections, including supply tubes and toilet bolts, to prevent cracks and leaks. When fixing a stuck shut off valve, be

5. Ignoring Water Pressure Regulation

Excessive water pressure can damage pipes, fixtures, and appliances over time. Ignoring water pressure regulation or using incorrect pressure-reducing valves can result in leaks, bursts, and premature wear and tear. Ensure that your plumbing system includes proper pressure regulation to protect your investment and prolong the lifespan of your plumbing components.

6. Inadequate Insulation

In colder climates like Tacoma, WA, inadequate insulation of pipes can lead to frozen pipes and potential bursts during winter months. Properly insulate exposed pipes, especially in attics, crawl spaces, and exterior walls, to prevent freezing and costly water damage.

7. Common Plumbing Mistakes (DIY)

8. Overlooking Future Expansion Needs

Failing to plan for future plumbing expansions or changes can be a significant oversight. Whether it's adding a bathroom, expanding a kitchen, or installing new appliances, it's essential to anticipate potential future needs. Including extra supply lines, drainage connections, and accessible shut-off valves can save time and money down the line. Many homeowners want to add a utility sink in their garage after a home is built. Will this be easy to do in your new home? Your plumbing layout and decision making can make all the difference.

9. Incorrect Pipe Material Selection

Choosing the wrong pipe material for specific applications can lead to premature failure and other issues. For example, using PVC pipes or plastic pipes for hot water lines or not considering the corrosive nature of certain water supplies can cause leaks and contamination. Ensure that you select the appropriate materials for different parts of the plumbing system based on usage, temperature, and local water quality. You'll want to check your local building codes or work with a licensed plumber to be sure that you use the proper pipe material. Each of these materials below suits specific applications based on factors such as water pressure, temperature, installation environment, and budget.

What are the most common plumbing pipe materials?

Copper
PVC (Polyvinyl Chloride)
CPVC (Chlorinated Polyvinyl Chloride)
PEX (Cross-linked Polyethylene)
Galvanized Steel
ABS (Acrylonitrile Butadiene Styrene)
Stainless Steel
Cast Iron

10. Improper Fixture Installation

Incorrect installation of fixtures such as sinks, toilets, and showers can result in leaks, poor functionality, and water damage. Common issues include using the wrong sealants, failing to secure fixtures properly, or not aligning them correctly with the plumbing connections. Always follow manufacturer instructions and hire skilled professionals to ensure fixtures are installed correctly and securely.

By avoiding these 10 common plumbing mistakes and working with experienced local professional plumber like Royal Flush Plumbing LLC, you can enjoy a reliable and efficient plumbing system in your new home. Contact us today for expert rough in or new construction plumbing services and peace of mind in Tacoma, WA and nearby area.

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Hot Water Troubles? When to Repair or Replace Your Water Heater

December 2, 2025

There's nothing quite like the shock of stepping into a morning shower only to be hit with ice-cold water. Or finding a puddle around your water heater. Or fiddling with the pilot light for the third time this month, wondering why it won't stay lit. When your water heater starts acting up, you face an immediate question: Can this be fixed, or is it time for a new one? Getting it right can save you hundreds—or even thousands—of dollars. Let's walk through what you need to know. Average Lifespan of Water Heaters Traditional tank water heaters (gas and electric) typically last 8 to 12 years . Gas models may wear out closer to 8-10 years, while electric tanks often reach 10-12 years with proper care. Tankless water heaters can last 15 to 20 years or more with regular maintenance. The trade-off is higher upfront cost, but extended lifespan often balances that out. Several factors shorten lifespan: hard water accelerates corrosion, sediment creates hot spots that damage tank lining, and neglected maintenance turns small problems into big ones. If your water heater is approaching its expected lifespan, have a professional look—even if it's still working. Catching problems early gives you time to plan rather than scrambling for emergency replacement. Signs It's Time to Replace Some symptoms mean it's time to shop for a new water heater: Rusty or discolored water from hot taps signals tank corrosion. Once rust starts, it doesn't stop—and a corroded tank will eventually leak. Leaks or moisture at the tank base mean the inner lining has failed. There's no fixing this. If you see water pooling, plan for replacement immediately before a small leak becomes a flood. Loud popping or rumbling noises indicate serious sediment buildup. If your water heater sounds like a popcorn machine, damage may already be done to heating elements or tank lining. Repeated pilot light failures on gas units—especially after replacing the thermocouple—suggest deeper problems with the gas valve or control system. Rising energy bills without increased usage signal lost efficiency. An aging unit works harder to deliver the same hot water, driving up utility costs monthly. Age plus any major issue is the clincher. If your water heater is over 10 years old and showing these symptoms, replacement almost always makes more financial sense than repair. When a Repair Might Be Enough Not every problem means game over. Some fixes are straightforward and cost-effective: Thermostat issues on electric heaters are inexpensive to fix Heating element replacement restores full function for a fraction of replacement cost Pilot light components like thermocouples are relatively cheap to replace Pressure relief valve replacement is a simple safety-critical fix Annual maintenance like flushing and anode rod checks prevent major problems The key question: How old is your unit? Under 6 years with a minor repair? Fix it. Over 10 years? Even modest repair costs might be better spent toward a new, efficient unit. Upgrade Options for Tacoma Homes Tankless water heaters offer compelling benefits: endless hot water on demand, 20-30% energy savings, space savings with wall mounting, and 15-20+ year lifespan. Trade-offs include higher upfront cost (2-3 times a tank heater), proper sizing requirements for peak demand, and installation complexity that may require upgraded gas lines or electrical service in older homes. Good news for Tacoma homeowners: many older homes in Stadium District, North End, Hilltop, and surrounding neighborhoods can accommodate tankless retrofits with minimal modifications. A qualified plumber can assess your setup. If tankless doesn't fit your budget or home, upgrading to a high-efficiency tank water heater still delivers significant energy savings. Cost Factors and Timelines Repairs: Most complete in 1-2 hours during a single service call. Common repairs typically range from $150 to $500. Replacements: Tank-to-tank replacement takes 2-4 hours. Tankless installations may take a full day or two visits. A reputable plumber provides clear diagnosis before starting work, explains options honestly, offers upfront pricing, and discusses financing if needed. Many companies offer payment plans that make upgrading affordable. Maintenance to Extend Lifespan Flush annually to remove sediment buildup. Set temperature to 120°F —hot enough for household use while reducing corrosion and energy waste. Check the anode rod every 2-3 years; replacing this $20 part beats replacing a $1,200 heater. Schedule professional inspections if your unit is over 6 years old. Don't Gamble With Your Hot Water Water heater problems rarely resolve themselves. That strange noise or occasional cold shower is your first warning—ignoring it risks complete breakdown at the worst time. Ready to find out what's going on? Schedule an inspection today. We'll give you an honest assessment, explain your options clearly, and help you make the right decision for your home and budget. Serving Tacoma homeowners with straightforward plumbing solutions. Because you deserve reliable hot water—and honest answers.