Plumbing Basics: A Homeowner’s Guide from Castle Building Supplies

Plumbing has a reputation for being intimidating — mostly because a small mistake can mean water where you don’t want it. But most residential plumbing projects come down to understanding a handful of pipe types, fittings, and fixtures. Once you know what you’re looking at on the shelf, a lot of common repairs and upgrades become a lot less mysterious.

Here’s a straightforward rundown of what you need to know before your next plumbing project.

Common Pipe Materials

Not all pipe is created equal, and the right choice depends on what it’s carrying and where it’s going.

• PEX (Cross-Linked Polyethylene): Flexible, affordable, and the go-to choice for most modern water supply lines. It’s easy to run through walls and tight spaces, resists freezing better than rigid pipe, and doesn’t require soldering — just crimp or push-fit connections.
• Copper: The traditional standard for water supply lines. Durable and long-lasting, but more expensive and labour-intensive to install since it requires soldering (sweating) joints.
• PVC (Polyvinyl Chloride): Rigid white plastic pipe, most commonly used for drain, waste, and vent (DWV) lines rather than water supply. Lightweight, inexpensive, and simple to work with using solvent cement joints.
• ABS (Acrylonitrile Butadiene Styrene): Black plastic pipe, also used for drain and waste lines. Functionally similar to PVC, though local codes may specify which one is required in your area.
• CPVC: A close cousin to PVC that can handle hot water supply lines, used in some homes as a lower-cost alternative to copper.

Supply Lines vs. Drain Lines

It helps to think of your plumbing system as two separate jobs happening at once:

• Supply lines bring fresh water in under pressure — these are the pipes that need to hold up to constant pressure without leaking, which is why PEX and copper dominate here.
• Drain, waste, and vent (DWV) lines carry wastewater out using gravity, not pressure, which is why lighter materials like PVC and ABS are suitable for this side of the system.

Mixing these up — using drain-rated pipe on a pressurized line, for example — is a fast way to end up with a leak.

Fittings 101

Fittings are the connectors that let pipe change direction, branch off, or join to fixtures. A few you’ll run into constantly:

• Elbows: Change the direction of a pipe run, usually 45° or 90°.
• Tees: Split one line into two, commonly used where a branch line feeds off a main supply or drain.
• Couplings: Join two straight lengths of pipe together.
• Unions: Similar to a coupling, but designed to be taken apart again later — useful anywhere you might need future access, like near a water heater or fixture.
• Adapters: Transition between different pipe materials or thread types, such as PEX-to-copper or male-to-female threaded connections.

Shutoff Valves

Every fixture — sinks, toilets, washing machines, water heaters — should have its own shutoff valve nearby, so you can isolate that single fixture for repairs without cutting water to the whole house. If your home is missing individual shutoffs, it’s one of the more worthwhile upgrades you can make; a stuck or leaking valve is a lot less stressful to deal with when it’s isolated to one fixture instead of the whole system.

It’s also worth knowing where your home’s main shutoff valve is — this is the one that cuts water to the entire house, and everyone in the household should know where it is and how to use it before an emergency, not during one.

Water Heaters: Tank vs. Tankless

• Tank water heaters store and continuously heat a set volume of water, ready to use on demand. They’re generally less expensive upfront and simpler to install or replace.
• Tankless water heaters heat water on demand as it flows through, rather than storing it. They take up less space and can be more energy-efficient over time, but usually come with a higher upfront cost and may require upgraded gas or electrical service.

The right choice depends on household size, hot water demand, and available space — worth thinking through before a replacement rather than during an emergency swap.

Bathtubs, Showers & Shower Walls

Fixtures are where plumbing meets design, and it’s worth choosing carefully since these are pieces you’ll live with for years. At Castle Building Supplies, we carry MAAX, one of the top names in bathware, for exactly this reason.

• Bathtubs: MAAX offers alcove, freestanding, drop-in, and corner tub styles, so there’s an option whether you’re fitting a standard bathroom layout or building a statement piece into a larger renovation.
• Tub & Shower Combos: For a simpler, all-in-one install, MAAX’s multi-piece tub shower kits combine the tub and surround into a single acrylic unit, cutting down on installation time and seams where water could get in.
• Shower Bases & Walls: MAAX’s Utile line is worth a look if you like the appearance of tile without the grout maintenance — the wall panels are designed to mimic tiled surfaces while installing in a single day, directly onto the studs.

If you’re planning a bathroom renovation, it’s worth deciding on your tub or shower fixtures early, since they can affect your rough-in plumbing dimensions and framing.

A Few Signs You Shouldn’t Ignore

• Slow drains often point to a partial clog building up in the pipe — worth addressing before it becomes a full blockage.
• Water stains or soft spots near pipes, under sinks, or on ceilings below bathrooms usually mean a slow leak somewhere in the system.
• Fluctuating water pressure can indicate anything from a partially closed valve to a developing pipe issue.
• Unusually high water bills with no clear explanation are one of the most common ways homeowners discover a hidden leak.

Know When to DIY — and When to Call a Pro

Plenty of plumbing tasks are well within reach for a confident DIYer: replacing a fixture, swapping a shutoff valve, running a new PEX line, or fixing a running toilet. But anything involving your main water line, gas lines, or significant rerouting of drain lines is usually worth bringing in a licensed plumber — both for safety and because plumbing work is often subject to local code requirements.

Stop By and Ask

Whether you’re replacing a leaky valve or planning a full bathroom reno, Castle Building Supplies carries the pipe, fittings, and MAAX fixtures for the job. Bring in your project details — or even just a description of what’s going wrong — and our team can help point you in the right direction.