Plumbing Basics - Learn about your home plumbing system
Can’t fix a leaking tap? Don’t know where your water comes from, or even where it goes?
Whatever you need to know about your home plumbing system we’re here to help. We’ll help you satisfy your plumbing desires by showing you the difference between straight up, money-saving DIY, or those desperate times where you just need to get a plumber involved. But first, let's talk about your system itself.
Plumbing has, and always will, follow the basic laws of nature. These are gravity, pressure and water seeking its own level. When you understand this the magic and mystery surrounding what goes on in your pipes starts to make sense. Knowing what you’ve got can really save you time and money.
Any time you use a shower, tap or toilet your plumbing system is kicked into action, delivering either hot or cold water. It’s something that’s been around for many thousands of years, yet it still confuses a lot of people.
We have tried to keep this guide simple and give you as many tips as we can but please remember that all properties differ and if you are ever unsure get in touch with a qualified plumber.
Plumbing Basics Glossary
Our plumbing systems are BIG. They’re made up of a lot of different parts that go in and out of your home so to help you understand clearly we’ve put this glossary early on. Have a browse and familiarise yourself with what different things are. Some we will cover in more detail later too!
Waste water – This is any water that’s been used in a sink, toilet, bath or shower. The clue is in the name is it will pass throw a type of waste before leaving your home.
Gravity Fed (vented) system - Older style system featuring a cold water tank in the loft and hot water cylinder elsewhere.
Combi boiler system - Cold water is pumped through a combination boiler providing on demand hot water.
Unvented system - Essentially a vented system but without the cold storage tank in the loft.
Cold water tank - These are stored in your loft usually and keep a large amount of water. Gravity then takes this water to outlets in your home.
Booster pump - These can be connected to your shower to increase pressure and performance.
Thermostatic mixer shower - Thermostatic showers keep a consistent, safe temperature no matter what else happens in your home.
Water pressure - Pressure is the force in which water is pushed through pipes.
Drainage system - This is the water system that takes away any waste water from your home.
Trap - These are designed to keep bad smells from the drainage system getting back into your home.
Vent - This is where air is drawn into your house. Without them, waste water wouldn't flow properly.
Clean-out - This is an easily accessible part of pipework that your plumber can access.
Stop cock/ stop valve/ stop tap - The main switch off for water coming into your home.
Indirect cylinder - This is heated by a combination boiler.
Direct cylinder - This is heated by electric elements within the cylinder.
Overflow (or warning pipe) - This stops indirect system tanks from overflowing.
Cold feed - This is the main water source into your home. It feeds cold outlets and the hot water system.
Float Valve/ Float Operated Valve/ Ball valve - This floats on top of your attic water storage tank. It's connected to a lever that closes when the tank has reached capacity.
Right now we’ve covered some basic terms it’s time to get into the nitty-gritty of it!
How does your home plumbing work?
First of all let’s start with the basics.
The plumbing system in your home is made up of two different systems. One that brings clean, fresh water in and another (the drainage system) takes the waste water back out again.
The water coming into your home is already pressurised which forces it to travel in straight lines, round corners, and upstairs. Essentially any place that you might need it. If you’re on a water meter then it’ll be fitted somewhere near where water enters your home for precise recordings. Your stopcock will also be fitted near this location, usually underneath your kitchen sink.
Whenever you move into a property finding your stopcock should be a priority. Should the worst happen and you spring a leak then you need to be able to turn off your water as quickly as possible. Modern homes also have stop valves fitted to appliances like sinks, toilets, baths or showers too, these allow you to isolate just that water source rather than turning off the entire system. If you want to know more about caring for your stopcock we’ve put some extra information further down this article.
Anyway, back to the system itself! The pressurised water coming into your home is cold so if that’s what you need then you’re ready to rock’n’roll. If you want hot water though there is a bit more to the process. A dedicated pipe takes water from the cold feed and directs it to your water heated, whether that be a combi boiler or a hot water cylinder. Here the water is heated and sent out to any part of your home that requires it.
When you’ve used the water it becomes waste water. Simple as that. Waste water is then disposed of, you guessed it, through a waste into the drainage system. As we’ve already covered, pressure helps water get into your home, well to leave, all it needs is gravity (and a bit of air). Waste water pipes are ever so slightly angled ensuring that it can easily and effortlessly flow out and away from your home until it reaches a sewer or septic tank. Although you need one more thing to ensure this system works, and we’ve mentioned it above. Air.
No drainage system would be complete without a set of vents or traps. These help to control the air that gets into your waste water.
Vents allow air to enter the pipework, usually located on the roof of your home or somewhere elevated. This air helps to propel the water through the drainage system. Without it, your waste water probably wouldn’t flow as efficiently as it needs to.
Traps are also a really crucial part of your waste water system. The clue as to what they do is in the name, they essentially trap things, in this case, air. When you flush something away or wash something down the sink you often forget about it, more than likely because it doesn’t smell. Well, the lack of stench is because of a cleverly designed trap, either at the back of your toilet or under your kitchen sink. These are curved sections of pipework that hold a small amount of water. This water fills the pipe and creates a seal which in turn stops any old or awful smells from getting back into your home. Any water fixture in your home should have a trap fitted.
For the most efficient water system, all components need to be in perfect working order. We definitely recommend working out what kind of plumbing system you have and learning where essential parts are to minimise panic in emergencies. Maybe take a look at the different traps, valves and pipes you have too.
For minimal worry, you may also want to consider some form of home emergency cover, whether that’s provided by your insurance company or a service you pay for separately. A fast response when a serious leak is present could make all the difference!
Different types of water systems explained:
There are three main types of water systems and we’re here to try and guide you through them. Whether you’re looking to update yours or you’re just not sure which you have, you’re in the right place!
Gravity-fed water system (also known as a vented system):
Image courtesy of Mira Showers
These are one of the most popular systems in UK homes, commonly found in older properties, they are terrible for low water pressure and flow. They feature a hot and cold water feed, with a large cold water tank often fitted in the loft and a large water cylinder taking up yet more space in the airing cupboard. The cylinders are what provide the hot water, being heated by either a boiler or an immersion heated within it.
As mentioned above, pressure can be somewhat poor on a gravity-fed system. This is because it depends largely on the distance from the bottom of the tank in your loft to your shower head. Gravity creates the pressure, the bigger the gap the greater the gravity and in turn the greater the pressure you get. 3 to 4 metres is generally the recommended distance for a decent amount of power.
Gravity-fed systems are the only water systems that you can use an additional pump on. These are fitted to the hot water cylinder and can be used with multiple showers simultaneously. Talking from experience, they really do turn a normal shower into something of a spa treatment.
Gravity fed system advantages
- Gravity-fed (vented) systems are normally cheaper to install and maintain.
- You always have reserve water in the loft if the mains supply goes off.
Gravity fed system disadvantages
- You need a decent height between the water outlet and your tank otherwise the water pressure will be low.
- A shower pump is often needed to boost water flow.
- Cold water storage tank in the loft takes up a lot of space.
Combi (combination) boiler system:
Image courtesy of Mira Showers
Combi boiler systems are becoming ever popular. They don’t use a water tank in the loft or a water cylinder in your airing cupboard, so you’ve already gained valuable space. To function, a combi boiler system uses just the mains pressure to deliver water to all the outlets in your home, pre-heating the water that you need rather than storing it in a large tank. These systems generally have the highest water pressure and are perfect for use with mixer showers.
One thing we would recommend when buying a shower for a combi system is to get something that’s thermostatic, especially if it’s a mixer shower. A thermostatic shower monitors the incoming water and adjusts it accordingly, so a stable temperature is always held. This stops you get shot with hot or cold water, something that could potentially harm the user.
Combi boiler advantages:
- Water is heated on demand from the mains.
- No storage tank or hot water cylinder is required.
- No additional shower pumps are needed as water is mains pressure.
- Greater flexibility over what works for you and your home. Boilers are available in a number of sizes and outputs.
- No risk of frozen pipes as there’s no cold water tank in your attic.
Combi boiler disadvantages:
- Multiple people using multiple showers may lower your water pressure. Something that’s not ideal for large families.
Image courtesy of Mira Showers
Unvented systems also require a separate hot water tank, usually in the airing cupboard, but they don’t use a tank in the loft for cold water. Instead, the mains water feed goes straight into the cylinder where it is kept pressurised. Here it is heated by either a combi boiler or an immersion heater. It then can provide large volumes of hot water to your shower at one time. Now the issue here is that it is possible to run out of hot water, you’ll then need to wait for the tank to heat up again before getting more.
An unvented system is effectively ‘sealed’ so an expansion vessel is needed either next to the boiler or incorporated into it. This expansion vessel allows for the expansion of the water as it heats up.
Unvented system advantages
- No water tank means less wasted space and quieter operation.
- Gravity isn’t needed so installation almost anywhere is possible.
- A completely sealed system reduces risk of contamination.
- Better flow rates thanks to mains pressure.
Unvented system disadvantages
- Often more expensive to install and maintain.
- Won’t provide hot water if your mains water is off.
- Not always compatible with modern mixer showers and power showers.
Cold mains system:
Image courtesy of Mira Showers
If you’ve got no stored hot water or you don’t want to use all your hot water up when you shower then you can fit an electric shower to a cold mains system. You can use electric showers specifically because they have an internal element that heats the water before delivery. The amount of hot water is usually measured by kilowatts (kW), with the higher ratings providing better flow rates.
Cold mains supply advantages
- Great solution if you don’t have any stored hot water.
- No hot water cylinder saves space.
Cold mains supply disadvantages
- Restricted to only electric showers as you need an element to heat the water.
- Needs mains water to operate.
Our top 10 plumbing tips
Never ignore something that’s leaking
They’re usually caused by loose connections, broken seals or clogged pipes, none of which you want to ignore. But hey who are we to tell you what to do? It’s just a small wet patch, right? Wrong. The majority of your pipework is hidden away and you actually have no idea how much unseen damage that leak could be doing. We recommend regularly checking fixtures, toilets, taps, kitchen sinks (anything that uses water!) for leaks.
Know how to use your stopcock (and where it is!)
If you spot a leak you want to stem it as soon as possible. Either isolate the shut-off valve at the fixture or hit the stopcock to complete You may want to turn your water off if you’re going away for a long period of time too.
Check for existing pipes and wiring
If you plan on drilling holes, whether that be in your walls, floors or ceilings, make sure to do thorough checks on what’s behind or beneath them. If you puncture a supply or drainage pipe then you risk serious leaks, but if you drill through a live wire you risk even worse, so be cautious and borrow or invest in a pipe and live wire detector.
Know what goes down the toilet
Toilets aren’t water filled rubbish bins, we should all be very particular about what goes down them because it can cause blockages, not just in your drainage system but further down the line too. There can be some seriously hefty bills for dealing with blockages so the best way to avoid them is by only flushing toilet paper.
Don’t wash food waste down your sink
Plumbing doesn’t just relate to your bathroom, it applies to anywhere that uses water in your home, including your kitchen sink. And the same rules apply here as they do almost everywhere else, your sink is just for getting rid of water, not food waste. Food waste, and worse yet cooking fat, can block drains badly! You never heard of a Fatberg?
Lefty Loosey, right not too tighty!
Many people make the mistake of thinking that everything needs to be done up really tightly. That really isn’t the case and one of the most common plumbing mistakes is to over-tighten connections or fittings. You risk doing more damage this way which means getting a real plumber in to redo the work.
Make sure you’ve got the right tools
We’re not saying you need to spend a fortune but we think, at the very least, you need some of these tools to make your life easier.
Plungers – valuable for clogged drains
Drain snake – unblocks drains too, used for clearing hair without damaging pipes
Spanners – Adjustable spanners are the most versatile. You’ll need them for almost any plumbing job
Slip-joint pliers – Ideal for fishing small things out of tight places
Screwdriver set – most isolating valves need a large flat head to turn them. Make sure you’ve got some
Rubber gloves – protect yourself from chemicals or sharp edges with heavy-duty rubber gloves
Yep, that’s correct, you should give your stopcock a little TLC every so often. They’re the key to stopping major leaks should something go wrong so ensuring it’s in full working order occasionally is a must. All you need to do is apply a squirt of WD40 lubricant every now and then to keep it easy to turn. The last thing you want in an emergency is an unnecessary fight on your hands.
Don’t forget the PTFE tape!
PTFE tap, also known as plumber’s tape or Teflon tape, makes achieving a watertight seal on threaded pipe joints much easier. And when the time comes to take things apart it also allows for easier loosening. Make sure you’ve always got a roll or two on standby, you can buy some here if you need any.
Don’t skimp on a plumber if you need one!
Probably the most important rule here because getting someone underqualified means you’re in for a world of expenses! So if you think your DIY knowledge is at its maximum, or that YouTube tutorial just doesn’t make sense then give the professionals a call, and we’re not talking Mario and Luigi! If you’ve got a friend or family member in the trade then even better.
We would recommend always having a name and number to hand as you don’t want to be trawling through Trustpilot or Google reviews in times of emergency. Make sure they’ve been in the business for a while and check and make sure they’ve got a good reputation.
Simple plumbing how-to guides
How to get rid of suspicious smells
As we’ve mentioned, all parts of your waste water system have a trap fitted to stop bad smells from entering your home. Now a bad smell might be because of a blockage you can’t see or simply because your trap has managed to empty. If it’s emptied you could fix the issue by simply running the tap to fill it again. If it’s blocked you may need to remove the pipework to remove the problem. This isn’t a particularly difficult job as most traps have screw fittings on either end to allow easy removal. Simple unscrew, remove the blockage and screw back into place, voila!
What to do with blocked drains
This leads on a little from suspicious smells because blocked drains can sometimes stink! The most common places for blockages or slow draining water is the bath or shower. Long hair and skin cells combine with soap and shampoo scum to really cause drainage issues. Sometimes they’re fairly simple to fix as the hair is tangled around the plughole but most of the time the problem occurs deeper down in the waste. For this, you can get yourself a plumbing snake, which is essentially a flexible rod that gets poked down the plughole. A hook on the end grabs hold of the blockage and pulls it up out of the plughole.
You can get chemicals to do the same job but they aren’t always great for the environment so be careful with what you use. For something a bit more eco-friendly you could try vinegar or bicarbonate of soda which are readily available in most shops.
How to remove limescale
Limescale is one of those things that plagues us all, especially if you live in a hard water area. It builds up on taps, drains, shower heads and basically anything that uses water. It can be a real difficulty to get off with a cloth but with a bit of vinegar, or better yet a high-quality tap cleaner, your chrome, enamel or acrylic will look perfect again. Our bathroom cleaners can be found here.
How to use a plunger
Most blocked drains or overflowing toilets and basins can be dealt with by a plunger. In fact, they say that 90 per cent of all clogs can be removed by one, so if it’s that or getting an expensive out of hours plumber in then we know what we’re trying first!
Believe it or not but the first thing you need to know about plungers is they aren’t all the same. Your local DIY shop might have a whole shelf of them but we think there are only two that you’ll really need for domestic use. These are “the cup plunger” and “the flange plunger”.
The cup plunger is your stereotypical looking plunging device, it’s sometimes known just as a standard/sink plunger. With its long wooden handle with a large rubber cup attached to the end of it, it’s ideal for any drains on a flat surface because that’s where it creates the best seal. So, for your bath, your basin, your kitchen sink, the cup plunger is just the right tool.
The flange plunger, also known as a toilet plunger, is what you need in a real emergency! These devices have an extra rubber ring around the cup, called the flange, which helps to keep that seal when you’re plunging.
Now you know which plunger you need to use you can work on your form. Forget everything you’ve been told because trying to flush that blockage out while plunging won’t work. All you’ll succeed in doing is breaking your plungers seal which is not ideal.
Our biggest top tip for plunging surrounds drain-clearing chemicals. Don’t use them at the same time as a plunger. You really don’t want to end up with toxic substances splashing around, they can cause burns to the skin and worse to the eyes so just don’t!
How to plunge a sink, shower or bath
Right, we already know for a job like this we need to be using the cup plunger because it’s on a flat surface. So, start by covering any overflow because air getting in and out of there will reduce the amount of suction that you’re going to be getting. Use a wet towel for this if you’ve got a spare one. You may also want to seal off any other drains nearby whether that be the basin or bath, this will give you better results too.
For best results use something like petroleum jelly in small amounts as this will create a much tighter seal around the rim of the cup.
Now for the plunging itself! Place the cup directly over the drain and press down. If you’ve got too much standing water, you may need to bail some out first as you’re going to make a lot of mess otherwise. Push the plunger handle down gentle to force the air out of it and to create that valuable seal. Then plunge quickly and accurately. Make sure to keep the plunger straight so that all pressure is directed straight down the plughole. Your thrusting shouldn’t be so powerful that you dislodge the plunger on the up pulls, remember to keep it sealed tightly. After approximately 20 or 30 seconds the drain should be clear.
How to plunge a toilet
Plunging a toilet uses very much the same technique as a sink or bath. There are however some things to note before you start. If your toilet is too full, you’ll need to wait 5 or 10 minutes for it to drain or if it’s really full bail some water out of it. When the pan is halfway full, turn off the water supply to stop it from continuously filling, this is usually found behind the pan. If the toilet pan is empty of water, then again fill up to the halfway point because enough water to cover the flange will create a better seal and make your life easier.
Again, for the plunging itself place the cup directly over the drain and press down. Keep the plunger straight so that all pressure is directed straight down the toilet waste. Press down gently to remove air from the plunger and to create that all-important seal. Then trust as powerfully as you can without breaking the seal between plunger and pan. After approximately 20 or 30 seconds the toilet should drain correctly again.
When does the water in my home become my responsibility?
No one likes dealing with a blocked drain but sometimes it can be a bit unclear as to who, exactly, should be dealing with it. A general rule of thumb is, if it’s only your property (whether that’s in the house or not) then it’s your job to get it sorted.
If the problem lies within the lateral drains or sewer then your local water company is responsible for fixing this.
If there are issues with blocked drains within a rented property then it is usually the landlord's responsibility to get the problem fixed.
If you found this useful you may also like - Plumbing Costs Estimates: From an Install to a Pipe Repair - DIY Home Improvements - Bathroom DIY: How to Fit a Toilet.
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