Contents (Click To Jump)
- 1 How Does a Garbage Disposal Work?
- 2 What Do You Need To Know About Installing a Garbage Disposal?
- 3 How Much Does Installing a Garbage Disposal Cost?
- 4 How Do You Install or Replace a Garbage Disposal?
- 5 When Should You Hire a Professional to Install/Replace a Garbage Disposal?
- 6 What Should You Look For in a Garbage Disposal Installer or Repair Specialist?
How Does a Garbage Disposal Work?
Before we dive into the installation costs, let’s quickly review how your garbage disposal works so you understand how installation works and what problems indicate you need a replacement!
In short, your kitchen sink pulls in water from your water supply lines to feed the faucet, and that used water then falls out of the drain, passes through the trap beneath the sink, and enters into your drainpipe.
The drainpipe typically travels through your floor and delivers wastewater to your main sewer line, which is connected to your public sewer system, cesspool, or septic tank for proper and safe removal of waste.
A garbage disposal is an electric device that intercepts water leaving your kitchen sink, churns, and grinds food scraps and other material caught in the water when the push-button is pressed, and then delivers the mixture of ground waste and water to your drain pipe for proper disposal.
Many homeowners use their sink to clean food off of dishes, and without a garbage disposal, the larger pieces of food waste can build up in the trap, drainpipe, or sewer line and cause a severe clog.
Clogged plumbing can cause water to back up to your fixtures, as well as slowly draining or totally blocked sink drains.
A garbage disposal not only makes the waste more manageable so that it can easily flow through your plumbing system without causing problems, but it also eases the burden on your septic system if you have one.
What Do You Need To Know About Installing a Garbage Disposal?
Installing or replacing a garbage disposal may seem like a straightforward task, but improper installation can cause severe leaking and water damage and necessitate costly repairs.
Knowing how the equipment works and how it is meant to interact with your plumbing can help you complete a successful installation or allow you to address issues after a plumber installs it for you.
How Does a Garbage Disposal Connect to Your Plumbing?
The plumbing beneath your sink may be confusing enough without a garbage disposal, and the additional equipment may make maintenance to the area inaccessible to you.
Understanding how a garbage disposal functions within your plumbing is crucial before installing or replacing your own.
The top of a garbage disposal is where water and food waste are taken in, so this portion usually attaches directly to the bottom of your kitchen sink drain. Your disposal will typically have two different pipe connectors protruding from its body, one small and one large.
The large pipe connection is meant to link up to your P-trap or S-trap and serves as the discharge site. After being ground, water and food material move toward this connection, fall into your trap, and then move onto your drainpipe toward your main waste line.
The smaller connection – if your disposal has one – is the dishwasher drain connector. This is another intake port that will collect wastewater from your dishwasher. The connection is typically sealed on new garbage disposals, and you’ll have to punch out the seal if you want to hook up your dishwasher waste line to it.
Why Do Garbage Disposals Need to Be Installed or Replaced?
Installing a garbage disposal under a kitchen sink that isn’t fitted with one already is wise, mainly because it can limit plumbing problems, clogged sinks, and backed-up kitchen sink drains.
Large food particles that are chewed up by a disposal can otherwise get caught in your trap or further down in your plumbing lines, causing blockages and potentially requiring replacement of part of your waste management system.
The primary reason for replacing a garbage disposal is that the motor wears out. Most modern disposals have a lifespan of about ten years, after which the motor will degrade, become less efficient, and stop working.
When this happens, it’s time to replace the disposal with a newer model.
Many homeowners with older disposal find that the noise is the biggest issue rather than a degrading motor. Older disposals typically don’t have noise-dampening and anti-vibration seals, baffles, or mounting brackets.
As a result, the disposal may shake violently when in use, creating loud noises that reverberate through your kitchen.
Most garbage disposal blades become dull or damaged over time and fail to grind food properly. If you’ve had your disposal in use for over ten years, it’s probably a good idea to have it replaced to ensure that it runs efficiently and can churn up food waste properly so as not to clog your plumbing.
When Do Garbage Disposals Need to Be Installed/Replaced?
If you don’t already have a garbage disposal working under your kitchen sink, it’s an excellent time to have one installed.
Standard plumbing pipes can quickly become clogged with food waste and other debris, and a disposal will help limit blockages and potentially expensive plumbing repairs down the road.
If you already have a garbage disposal installed, you should understand the common issues that can result from an older or defective model so that you can replace them before they cause more significant problems.
If you notice your disposal getting louder with age or if it becomes loud enough to interrupt a conversation or sleep in other rooms, it’s a good time to have your disposal replaced.
New models include noise-dampening technology that keeps the disposal running efficiently and quietly.
You should also consider replacing your unit if you frequently have to hit the reset button on your GFI outlet from a trip or electrical overload.
If you start to have recurring problems with clogs in your kitchen sink or your disposal jamming or shutting off due to no overload protection, these are reasonable indications that it’s time to replace your disposal.
If the blades dull or get damaged over time or if the motor loses power, the food particles entering your drain will be more likely to get caught in the trap. If these blockages go unrepaired, your sink may become unusable and the clogs can become so severe that parts of your plumbing system need replacement.
Leaks from your garbage disposal unit or resulting corrosion on any portion of the disposal are good signs that it should be replaced. We recommend having a plumber inspect the leak first, as it may be coming from other plumbing equipment or may just require that connections or gaskets be swapped out for new ones.
However, significant leaks may indicate that parts of your disposal are damaged beyond repair.
Finally, as mentioned above, you should aim to replace your garbage disposal with a new unit about once every decade, even if you don’t experience any problems.
Is a Leaking Garbage Disposal a Severe Problem?
Most leaks from garbage disposal are relatively minor and may not seem like something that should be considered an urgent problem. However, even small leaks can cause significant property damage and should be repaired immediately.
Most garbage disposals that leak do so from the connections to the sink drain, the trap, and the dishwasher. Generally, the leaking is slow and may barely be noticeable. Even slow drips can cause water damage to your cabinets and eventually your subfloor over time. Moisture can lead to wood rot, which deteriorates your construction material and can be very expensive to replace.
Moisture accumulation can also promote mold growth, which is not only costly to remediate but can also compromise your indoor air quality. Sensitive homeowners can experience anaphylactic shock, while others may only notice allergy symptoms.
In either case, inhaling mold spores is potentially dangerous.
Lastly, your garbage disposal uses electricity to power the motor and, as most homeowners know, water and electricity don’t mix well.
A leak from your garbage disposal could reach the electrical connections in your unit, potentially shorting your circuit breaker or causing a fire. As you can imagine, large-scale property damage is possible if this occurs.
Can You Install/Replace a Garbage Disposal Yourself?
Installing and replacing a garbage disposal can be done by handy homeowners, provided they have some experience with plumbing fixtures and electrical work and know how to create proper seals using PVC pipe.
While the process is doable as a DIY home improvement project, we always recommend that installing or replacing a garbage disposal – or any work that involves electricity and water – be left to a certified plumber for proper installation. Mistakes can be very costly and potentially dangerous, so only attempt the job yourself if you have experience with electrical wiring and plumbing projects.
How Much Does Installing a Garbage Disposal Cost?
Your unit price will be the biggest cost factor when it comes to installation or replacement. Disposal costs can range from approximately $75 for a cheaper batch feed garbage disposal – like a Waste King – up to about $350 for a high-end continuous feed garbage disposal – like an Insinkerator.
Additionally, the bigger the motor size and the more horsepower your unit has, the more food and debris it will be able to handle with ease. The style and capability can affect the pricing quite a bit.
Your garbage disposal installation cost will depend on the unit you intend to purchase, whether you pay labor costs for a plumber to do the installation, and whether there is already a grounded electrical outlet located beneath your sink. If you have an outlet already, your cost for tools and equipment will be around $75, plus the additional cost of the disposal.
The national average cost to have a plumber install a garbage disposal for you is around $400, including parts and labor. This price can fall anywhere between $200 and $1,000 for varying models and different plumbers.
Garbage disposal replacement costs typically fall between $150 and $250, not including the cost of the unit.
If you don’t have a grounded outlet under your sink already, you can expect to add around $100 to have an electrician install one for you.
How Do You Install or Replace a Garbage Disposal?
The first step to installing or replacing a garbage disposal is to cut power to the unit at the breaker. This is a crucial step that will prevent you from shocking yourself and causing a fire in your kitchen. Double-check that the power to the unit is off by attempting to turn it on.
Your next step will be to disconnect the drain pipe that leads to the trap, which is often attached with a screw-on coupling. Next, remove the dishwasher drain line if you have one connected.
Once the garbage disposal is only connected to the sink drain, unscrew the disposal from the stainless steel mounting bracket. The mounting assembly is typically held on with a snap ring, so pulling this off will release the entire assembly.
Make sure you have a good hold of the disposal as you release it from the bracket, as it is rather heavy. Set aside the old disposal, and unscrew the mounting ring and drain from your sink body, making sure to scrape off any leftover plumber’s putty.
Place a new ring of plumber’s putty around the lip of the drain, fit the drain into the hole in the bottom of your sink, and then begin to attach the gaskets and mounting assembly according to your disposal’s directions. You may need help lifting the garbage disposal while you mount it to the bracket.
Once the disposal is mounted to the sink, you can begin to hook up the drainpipe and dishwasher attachments using couplings. After you’ve secured all of the attachments, run your sink for several minutes and check for leaks. If all pipes and connections remain completely dry on the outside, you can hook up the electrical components and restore the power.
Check out the below video for more information on replacing a garbage disposal:
When Should You Hire a Professional to Install/Replace a Garbage Disposal?
Installing or replacing a garbage disposal can be done by experienced DIYers if they have tackled electrical and plumbing projects successfully in the past. However, we generally recommend hiring a plumber to complete the installation of your new disposal, especially if you’re at all uncomfortable with the process. Electricity is challenging and dangerous to work with, so resorting to a professional is usually the best option.
Additionally, if your new disposal is the same size as the old one, the drainpipe and connections won’t need to be altered to hook it up to your waste lines.
However, larger or smaller models will require that you re-route your plumbing, which can be challenging for most homeowners and DIYers. We especially recommend hiring a professional if your new disposal isn’t the exact same size as your old one.
What Should You Look For in a Garbage Disposal Installer or Repair Specialist?
When you’re looking for a garbage disposal repair specialist or installer, we strongly recommend you limit your search to certified and experienced plumbers. General contractors and handymen may be able to do it for less money, but when it comes to plumbing and electricity mixing, it’s best to pay a premium for someone who will perform a safe installation.
Plumbers typically either charge a flat rate or an hourly rate for their services. For a relatively straightforward job like replacing or installing a garbage disposal, we suggest opting for one offering a flat rate. This will ensure you don’t pay more for slower work or delays in the job, and you’ll know upfront what your total cost is.
Finally, we recommend opting for a plumber who offers a satisfaction guarantee or warranty for the work, as they will be most likely to provide the best service.