How To Layout & Install Plumbing in a New House

Building a new house is an exciting milestone, but there’s a lot to think about beyond just walls, windows, and decor. One of the most critical systems in your home is the plumbing system. Get it right, and you’ll enjoy reliable water flow, efficient drainage, and minimal maintenance for years to come. Get it wrong, and you could be dealing with costly repairs, hidden leaks, or even water damage down the line.

This guide walks you through how to layout and install plumbing in a new house, covering key components, planning strategies, installation steps, and important considerations to ensure your new home’s plumbing system runs smoothly from day one.

Understanding the Basics of a New Home’s Plumbing System

Your home’s plumbing system is made up of two main components:

• Water Supply System – This includes all the water supply pipes that bring fresh water into your home from either the municipal water supply or a personal septic tank. It delivers water to taps, showers, appliances, and plumbing fixtures throughout the house.
• Drainage System – Also known as the Drain-Waste-Vent (DWV) system, this includes drain pipes, sewer lines, vent pipes, and other drain pipes that carry wastewater and solid waste away from your home. This system relies on gravity to ensure proper drainage and prevent unpleasant odours from backing up into the house.

Source

Properly installing these systems from the start will save you from future maintenance headaches and ensure everything operates efficiently.

How To Install Plumbing in a New House:

Before you even think about installing pipes, take time to carefully plan your plumbing layout. This involves deciding where plumbing fixtures, drainage pipes, and water supply lines will go to ensure everything is efficient, cost-effective, and meets local building codes.

Planning Your Plumbing Layout

1. Group Your Plumbing Fixtures

Keeping plumbing fixtures close together (e.g., positioning bathrooms, the kitchen, and laundry room near each other) can help reduce the amount of piping needed. This not only makes installation more efficient but also helps maintain strong water pressure and reduces the risk of leaks.

2. Plan for the Rough-In Phase

The rough-in phase is the stage where all major pipes are installed before walls, floors, and ceilings are closed up. Key steps include:

• Installing main drains, vertical drain pipes, and water supply lines.
• Placing vent pipes to ensure proper air circulation in the drainage system.
• Ensuring all pipe connections are secure before moving on to final fixtures.

3. Consider Future Maintenance and Expansion

While planning your plumbing system, think about accessibility. If you ever need to make repairs or modifications, shut-off valves and cleanouts should be easy to reach. If you plan on expanding your home later (e.g., adding a second bathroom), consider running extra water supply pipes now to save trouble later.

Related Reading: Your Home Renovation Plumbing Checklist

Installing the Water Supply System

The water supply system consists of all the pipes that transport clean water to your fixtures. Here’s how to install it properly:

1. Choose the Right Pipes

There are several options for water supply pipes:

• Copper Pipes – Durable, resistant to bacteria, and long-lasting. However, they are more expensive than alternatives.
• PEX Pipes – Flexible, affordable, and easy to install. Ideal for running water to multiple fixtures with fewer connections.
• PVC Pipes – Often used for cold water lines and outdoor plumbing, but not ideal for hot water.

2. Maintain Proper Water Pressure

Water pressure is key to ensuring steady water flow throughout your home. Install a pressure regulator if needed, and ensure supply lines are the correct diameter to maintain consistent pressure across multiple fixtures.

3. Install Shut-Off Valves

Shut-off valves should be installed at key points, including:

• Under each sink and toilet
• Near washing machines and dishwashers
• On the main water supply line

This allows you to isolate specific areas of your home’s plumbing system for repairs without shutting off water to the entire house.

Setting Up the Drainage System

Your home’s drainage system is responsible for removing wastewater efficiently while preventing clogs, bad odours, and water damage. Here’s how to get it right:

1. Install Main Drains and Sewer Lines

The main drain line connects to the municipal sewer system or a personal septic tank. It should have a downward slope to allow wastewater to flow efficiently. Incorrect slope angles can lead to blockages and slow drainage.

2. Properly Vent Your Drain Pipes

Vent pipes allow air into the drainage system, preventing suction that could slow down water drainage. Without proper venting, you may experience slow drains, gurgling sounds, or even sewer gas leaks.

3. Use Quality Toilet Flanges and Seals

A good seal around toilet flanges is essential to prevent leaks and unpleasant smells. Always ensure flanges are properly installed and securely fastened to the floor.

4. Consider a Sump Pump

If your home is in an area prone to flooding or has a basement, installing a sump pump can help prevent water damage by pumping excess water away from the foundation.

Connecting Plumbing Fixtures and Appliances

Once the main plumbing installation is complete, the next step is making the final connections for fixtures and appliances.

• Kitchen and Bathroom Fixtures – Sinks, showers, toilets, and bathtubs should be connected carefully to both water supply lines and drain pipes.
• Water Heater Installation – Whether you choose a traditional tank or a tankless boiler, ensure it’s installed according to manufacturer instructions and local building codes.
• Washing Machines and Dishwashers – These appliances require both hot and cold water supply lines and a drain connection.

You Might Like: Fitting a New Boiler? Here’s What To Do…

Avoiding Common Plumbing Installation Mistakes

Mistakes during the plumbing installation process can lead to major issues down the line. Here are some common pitfalls to watch out for:

• Not Following Local Building Codes – Always check local regulations to ensure compliance with pipe sizing, materials, and installation methods.
• Skipping Pressure Tests – Before closing up walls, test your water supply lines for leaks by pressurising the system and checking for drips or drops in pressure.
• Using Incorrect Pipe Sizing – Pipes that are too small can restrict water flow, while oversized pipes can lead to weak water pressure.
• Neglecting Vent Pipes – Without proper venting, your drainage system won’t function correctly, leading to slow drains and sewer odours.
• Improper Slope on Drain Pipes – Too much slope can cause water to drain too quickly, leaving solids behind and increasing the risk of blockages.

Read More: New House Plumbing Problems? Here’s What To Do…

Looking For New Home Plumbing Services?

Installing plumbing in a new house is a major project that requires careful planning, quality materials, and professional expertise. A well-installed plumbing system ensures efficient water supply, proper drainage, and minimal future maintenance.

If you need expert plumbing installation in London or Essex, Lazard Plumbing offers reliable services to ensure your new home’s plumbing system is set up for long-term success.

Whether your home is in need of a plumber for home renovations, plumbing, underfloor heating, gas boiler installation and central heating, power flushing, or bathroom refurbs, we can help!

For complete peace of mind home plumbing solutions, contact our friendly team on 01708 502 346.

---

How To Install Plumbing in A New House FAQs