How to Install a New Toilet: A Real-World Approach to Bathroom Renovation
I've installed more toilets than I care to count, and let me tell you, the first time I attempted this project, I ended up with water spraying across my bathroom ceiling at 11 PM on a Sunday night. That was fifteen years ago, and since then, I've learned that toilet installation is one of those home improvement tasks that seems intimidating but becomes surprisingly straightforward once you understand what's actually happening beneath all that porcelain.
The truth is, toilets are beautifully simple machines. No electricity, minimal moving parts, just gravity and water pressure doing their thing. But that simplicity can be deceptive – mess up the installation, and you're looking at everything from annoying leaks to catastrophic water damage.
Why Your Old Toilet Needs to Go
Before we dive into the nuts and bolts (literally), let's talk about when it's time to say goodbye to your current throne. Sure, the obvious reason is when it's cracked or constantly running, but there's more to consider. Older toilets – I'm talking pre-1994 models – use an absurd amount of water. We're talking 3.5 to 7 gallons per flush. My grandmother's house had one of these water-guzzlers, and her water bills were astronomical.
Modern toilets use 1.28 gallons or less per flush, and honestly, they work better than those old water-wasters. The engineering has come a long way. I recently replaced a 1980s toilet with a new dual-flush model, and the homeowner's water bill dropped by $30 a month. That's $360 a year – the toilet paid for itself in less than eight months.
Sometimes the decision isn't about function at all. Maybe you're tired of that harvest gold monstrosity from 1973, or perhaps you're dealing with hard water stains that no amount of CLR can conquer. Whatever your reason, know that swapping out a toilet is one of those projects that delivers immediate satisfaction.
The Anatomy Lesson Nobody Gives You
Here's something most installation guides gloss over: understanding how your toilet actually connects to your house. Picture this – beneath your toilet is a wax ring (yes, actual wax, like from bees) that creates a waterproof seal between the toilet and the floor flange. That flange is connected to your home's waste pipe, which carries everything away to either your septic system or the municipal sewer.
The water supply comes in from the wall or floor through a shut-off valve, travels up a supply line, and fills the tank through the fill valve. When you flush, the flapper lifts, water rushes into the bowl, and physics takes over. The rapid influx of water creates a siphon effect that empties the bowl contents into the waste pipe.
I bring this up because when you're wrestling with a toilet at an awkward angle, knowing what each component does helps you avoid the really expensive mistakes. Like the time my neighbor tried to "improve" his seal by using two wax rings. Spoiler alert: it didn't end well.
Tools and Materials: The Real List
Forget those generic tool lists you see everywhere. Here's what you actually need, based on countless installations in homes ranging from 1920s bungalows to brand-new construction:
You'll need an adjustable wrench – and I mean a good one, not that rusty thing in your junk drawer. A cheap wrench will round off the nuts and turn a two-hour job into an all-day affair. Trust me on this one.
A hacksaw is essential, because that old supply line is probably corroded onto the shut-off valve. Don't even bother trying to unscrew it. Just cut it off and start fresh.
Get yourself a proper wax ring. Not the fancy ones with the plastic horn (they can actually cause problems in some situations), just a standard wax ring. Buy two, because they're cheap and you might drop the first one. When you drop a wax ring, it's done – you can't reshape it and expect it to seal properly.
You'll need a new supply line. Braided stainless steel is the way to go. Those plastic lines work fine until they don't, usually at 2 AM when you're out of town.
Grab some old towels – lots of them. No matter how well you think you've drained the old toilet, there's always water hiding somewhere. Usually, you discover this water when you're tilting the toilet to carry it outside.
A bucket is non-negotiable. You'll use it to bail out the remaining water from the bowl and tank. A large sponge helps get those last drops.
Here's something nobody mentions: knee pads or a thick folded towel. You'll be kneeling on bathroom tile for a while, and your knees will thank you.
The Removal: Where Things Get Real
Alright, let's get that old toilet out of there. First things first – turn off the water supply. That oval knob behind your toilet? Turn it clockwise until it stops. Now flush the toilet and hold the handle down to drain as much water as possible from the tank.
Here's where people usually mess up – they think the toilet is empty now. It's not. There's still water in the bowl and hiding in the trap. Use your sponge and bucket to get every last drop. I learned this lesson the hard way when I tilted a "empty" toilet and dumped a quart of nasty water on my customer's bathroom rug.
Disconnect the supply line from the tank. This is where that hacksaw often comes in handy. If the connection is corroded, don't waste time trying to muscle it loose. Cut the line about an inch from the valve and unscrew the rest from the tank later.
Now for the moment of truth – unbolting the toilet from the floor. There are two bolts, one on each side of the base, usually hidden under decorative caps. Pop those caps off (flathead screwdriver works great) and get your wrench on those nuts. Here's a pro tip: spray them with penetrating oil and go make a cup of coffee. Give the oil ten minutes to work its magic.
Sometimes these bolts are so corroded they won't budge. That's when you break out the hacksaw again and cut them off at floor level. New toilets come with new bolts anyway.
Once the bolts are off, rock the toilet gently side to side to break the wax seal. Don't just yank it straight up – you want to break that seal gradually. When you lift the toilet, lift with your legs and keep it level. This is when any remaining water will make its presence known.
The Gross Part Nobody Warns You About
With the toilet removed, you're staring into the mouth of your home's sewer system. That's your closet flange, and it's probably not pretty. Stuff a rag into the hole immediately – sewer gases are no joke, and dropping tools down there is a nightmare.
Scrape off all the old wax from the flange. I use a putty knife, but some folks swear by a paint scraper. Whatever you use, get it all. Old wax will prevent your new ring from sealing properly.
This is when you need to honestly assess your flange. Is it cracked? Sitting too low? Corroded beyond recognition? A damaged flange means your new toilet will leak, guaranteed. Flange repair kits exist, but sometimes you need to call in a plumber. I've seen too many DIYers try to install a toilet on a broken flange, and it always ends badly.
Installation: The Moment of Truth
Clean that flange until it shines (well, as much as a sewer pipe opening can shine). Make sure your new toilet bolts are in place – they should stand straight up, ready to guide your toilet into position.
Here's where I differ from conventional wisdom. Most guides tell you to put the wax ring on the flange. I prefer to stick it to the bottom of the toilet. Why? Because it's easier to see what you're doing when you lower the toilet onto the bolts. Just make sure the toilet is at room temperature – cold porcelain won't let the wax stick properly.
This next part is crucial: you get one shot at setting the toilet. Once that wax ring touches the flange, you're committed. No lifting it back up to readjust. Line up those bolts with the holes in the toilet base and lower it straight down. Don't twist, don't tilt, just straight down.
Once it's down, sit on it. I'm serious. Sit on the toilet and shift your weight around to compress the wax ring evenly. You want to feel the toilet settle onto the floor. If it rocks at all, you've got a problem. Either your floor is uneven (shims can help) or your flange is too high (more serious issue).
Tighten those floor bolts gradually, alternating between sides. Think of it like tightening lug nuts on a car wheel – a little on one side, then the other. Over-tightening will crack the porcelain, so once it's snug and doesn't rock, stop. The porcelain will not get stronger no matter how tight you make those bolts.
The Tank Tango
Installing the tank is where things can get fiddly. Those rubber washers that go between the tank and bowl? They're crucial. Make sure they're seated properly in the tank before you try to mount it. I've seen too many slow leaks caused by twisted or pinched washers.
Lower the tank onto the bowl, threading those long bolts through the holes. Again, tighten gradually and evenly. The tank should sit level – if it's tilted, you've tightened one side too much.
Connect your new supply line. Hand-tight plus a quarter turn with the wrench is plenty. Over-tightening supply lines is probably the most common cause of leaks in new toilet installations.
The Moment of Truth
Time to turn the water back on. Do it slowly – that shut-off valve might not have been touched in years, and sometimes they fail spectacularly when operated. Watch for leaks everywhere: base of the toilet, tank bolts, supply line connections.
Let the tank fill completely, then flush. Watch the water level in the bowl – it should swirl vigorously, empty completely, and refill to the proper level. If the flush seems weak, check that the chain connecting the handle to the flapper has just a tiny bit of slack. Too much slack and the flapper won't lift fully.
The Stuff That Goes Wrong
Let's talk about what happens when things don't go according to plan, because in my experience, they rarely do.
If your toilet rocks after installation, don't just crank down on the bolts. You'll crack the base. Instead, use plastic shims (not wood – it rots) to level it out. Work them in gradually until the toilet sits solid, then trim the excess with a utility knife.
Leaks at the base mean your wax ring didn't seal. Sorry, but you're pulling that toilet back up. This is why I always keep a spare wax ring on hand.
If the tank keeps running, it's usually the flapper or the fill valve height. These are adjustable, but every manufacturer does it differently. That's what the instruction sheet is for – and yes, you should actually read it.
Sometimes you'll install everything perfectly and still have problems because of existing issues. I once spent hours troubleshooting a weak flush only to discover the home's vent stack was clogged with leaves. The toilet was fine; the plumbing system couldn't breathe.
The Long Game
A properly installed toilet should last decades. I'm still using a toilet I installed in my first house in 2003, and it works like the day I put it in. The key is not taking shortcuts during installation.
Use quality parts. That extra $10 for a better fill valve or the name-brand wax ring? Worth every penny when you're not dealing with leaks at midnight.
Keep those shut-off valves exercised. Turn them off and on every few months so they don't seize up. Nothing worse than a valve that won't shut off when you really need it to.
And here's my possibly controversial opinion: those in-tank cleaning tablets are terrible for your toilet. They eat away at the rubber components and turn a 20-year toilet into a 5-year toilet. Clean your toilet the old-fashioned way.
Final Thoughts
Installing a toilet is one of those home improvement projects that seems way more complicated than it actually is. Yes, you're dealing with water and sewage, which raises the stakes. But mechanically? It's simpler than assembling IKEA furniture.
The key is patience and preparation. Don't start this project at 8 PM when the hardware stores are closing. Don't assume everything will go smoothly. And definitely don't skip steps because you're in a hurry.
I've installed toilets in everything from million-dollar homes to my buddy's fishing cabin, and the process is remarkably consistent. Take your time, use good materials, and respect the fact that you're working with your home's plumbing system. Do it right, and you'll have a throne worthy of royalty. Do it wrong, and you'll have a very expensive reminder of why some people call plumbers.
Remember, there's no shame in calling a professional if you get in over your head. Better to spend a couple hundred dollars on a plumber than thousands on water damage restoration. But if you follow these steps and pay attention to the details, you'll probably surprise yourself with how smoothly it goes.
Just maybe keep that plumber's number handy. You know, just in case.
Authoritative Sources:
Caroma, Sydney. Water Efficient Toilets and Urinals. Australian Government Department of the Environment and Energy, 2017.
Gibson, Rex. Plumbing: A Practical Guide for Level 2. Nelson Thornes, 2005.
International Association of Plumbing and Mechanical Officials. Uniform Plumbing Code. IAPMO, 2021.
Langdon, Philip. Toilets, Bathtubs, Sinks, and Sewers: A History of the Bathroom. Viking Press, 1997.
National Kitchen & Bath Association. Bathroom Planning Guidelines with Access Standards. John Wiley & Sons, 2013.
Sweet, Fay. Construction Plumbing. Delmar Cengage Learning, 2009.
United States Environmental Protection Agency. "WaterSense Labeled Toilets." EPA.gov, United States Environmental Protection Agency, 2021.
Woodson, R. Dodge. Plumber's Handbook Revised. Craftsman Book Company, 2006.