What You're Replacing Matters More Than the Steps

Replacement means different things depending on what broke. Replacing a kitchen faucet takes an afternoon and a wrench. Replacing a water heater takes a plumber, a permit, and a day. Replacing an HVAC system takes a contractor, a permit, and several thousand dollars. Before you start, you need to know what you're actually dealing with — whether it's something you can do yourself, something you can do with a helper and a video, or something that requires a licensed professional and a building permit.

This guide walks you through the most common household replacements: faucets, fixtures, appliances, and systems. For each one, you'll learn what the job actually involves, what tools or skills you need, when to call a professional, and what permits or inspections might be required. The goal is to help you make a realistic decision about whether this is a weekend project or a call to a contractor.

Key Takeaways

  • Small replacements like faucets, light fixtures, and cabinet hardware usually need only basic tools and can be done in an hour or two.
  • Medium replacements like toilets, garbage disposals, and dishwashers require some plumbing or electrical knowledge and take half a day to a full day.
  • Large replacements like water heaters, HVAC systems, and roofing require licensed professionals, building permits, and inspections in most places.
  • Always turn off water or power before you start, and take photos of the old installation before you remove anything.
  • Check your local building code or call your city's permit office before replacing anything that connects to plumbing, electrical, or structural systems.

Small Replacements You Can Usually Do Yourself

Faucets, light fixtures, cabinet hardware, door handles, and weatherstripping are all designed for homeowner replacement. You'll need a basic toolkit: adjustable wrench, screwdrivers (Phillips and flathead), pliers, and possibly a basin wrench if you're working under a sink. Most of these jobs take less than an hour once you have the new part in hand.

Before you start, take a photo of the old installation from multiple angles. If it's a faucet, turn off the water supply valves under the sink (or at the main if there are no shutoff valves). If it's electrical, turn off the breaker. Remove the old part carefully — note where each screw goes and what order things came apart in. Bring the old part to the hardware store if you're not sure what size or type to buy.

The new part usually comes with instructions. Follow them exactly, because manufacturers design them for the most common installation. If something doesn't fit or doesn't line up, stop and look at the instructions again rather than forcing it. Most of these jobs have no permit requirement because they're like-for-like replacements of the same type of fixture.

Medium Replacements That Need Some Skill and Time

Toilets, garbage disposals, dishwashers, and interior doors fall into this category. These require you to understand how water, electrical, or mechanical connections work, and they usually take four to eight hours. You can do them yourself if you're comfortable following detailed instructions and troubleshooting when something doesn't fit quite right.

A toilet replacement means shutting off the water, draining the bowl, unbolting the old toilet from the floor, and installing a new one with a new wax ring (the seal between the toilet and the drain pipe). A garbage disposal means disconnecting the old one from the drain and the electrical outlet, then installing the new one in the same space. A dishwasher means disconnecting water inlet and drain hoses, the electrical connection, and the mounting brackets, then sliding the new one into place and reconnecting everything.

For these jobs, watch a video specific to your brand and model before you start. Bring the old part with you when you buy the new one so you can confirm the size and connection type. Most of these replacements don't require a permit if you're replacing like-for-like, but check your local code — some places require a licensed plumber or electrician to sign off on certain work.

Large Replacements That Require a Professional

Water heaters, furnaces, air conditioners, roofs, and major plumbing or electrical work must be done by a licensed contractor in most places. These systems connect to your home's main infrastructure, and improper installation can cause leaks, fires, carbon monoxide poisoning, or electrical hazards. Your city or county requires a permit for this work, and an inspector will check it before you can use it.

When you need a large replacement, call three contractors and ask for written estimates. The estimate should include the cost of the new unit, labor, any necessary permits, and a timeline. Ask whether the permit fee is included or separate. Ask what warranty comes with the unit and what warranty covers the labor. Ask whether they'll handle the permit or whether you need to pull it yourself (most contractors handle it).

Once you've chosen a contractor, confirm the start date and ask what you need to do to prepare. For a water heater, you may need to clear the space around it. For an HVAC system, you may need to may support the contractor can access your attic or basement. For a roof, you may need to move cars from the driveway. The contractor will pull the permit, do the work, call for inspection, and get the sign-off. Keep all paperwork — the permit, the inspection report, and the warranty — in a safe place.

Tools and Materials You'll Need

For small replacements, a basic toolkit is enough: adjustable wrench, two screwdrivers, pliers, a flashlight, and a bucket to catch water. For medium replacements, add a basin wrench (for under-sink work), a toilet flange wrench (for toilet bolts), and possibly a stud finder (for mounting brackets). For large replacements, the contractor brings their own tools and materials.

Always buy the replacement part before you start removing the old one. Take the old part with you to the store, or write down the brand, model, and size. If you order online, confirm the return policy in case the new part doesn't fit. For plumbing work, buy a bucket and some old towels — water will spill. For electrical work, buy a non-contact voltage tester so you can confirm the power is actually off before you touch anything.

Permits and Inspections

Your city or county requires a permit for any work that affects plumbing, electrical, HVAC, structural, or roofing systems. A permit costs money (usually $50 to $300 depending on the job) and requires an inspection after the work is done. If you do unpermitted work and later sell your house, the new owner's inspector will find it, and you may have to pay to have it redone by a licensed contractor.

Call your city's building or planning department and describe the work. They'll tell you whether you need a permit. If you do, they'll give you a form to fill out. Some cities let you pull the permit yourself; others require a licensed contractor to pull it. If you're hiring a contractor, ask them to pull the permit — it's part of their job. If you're doing the work yourself, ask the permit office whether a homeowner can pull a permit for that type of work in your area.

After the work is done, call the permit office to schedule an inspection. An inspector will visit, look at the work, and either sign off or ask you to fix something. This usually happens within a few days. Once it's signed off, you get a final permit card or certificate. Keep it with your home records.

When to Stop and Call a Professional

Stop if you turn off the water or power and it doesn't actually turn off — the shutoff valve may be broken or in the wrong place. Stop if the old part won't come out without breaking something. Stop if you're not sure which wire goes where, or if you're working on anything that carries 240 volts (like a dryer or range). Stop if the new part doesn't fit in the space where the old one was. Stop if you're working on a load-bearing wall or anything structural.

Calling a professional is not failure — it's the right choice when the job is outside your skill level or when the code requires it. A plumber or electrician can do in an hour what might take you a full day, and they carry the right tools and know the local code. If you've already started and gotten stuck, call them anyway. Most will charge a service call fee to come look at it, but that's cheaper than breaking something expensive or creating a safety hazard.

Frequently Asked Questions

Do I need a permit to replace a faucet or light fixture?

No. Faucets and light fixtures are considered like-for-like replacements and don't require a permit. You do need to turn off the water or power before you start, and you should follow the manufacturer's instructions for installation.

Can I replace my own water heater?

Most cities require a licensed plumber to replace a water heater because it involves gas or electrical connections and venting. Call your building department to confirm the rule in your area. Even if it's allowed, the work is heavy and involves high-temperature connections, so hiring a professional is usually the safer choice.

What's the difference between a permit and an inspection?

A permit is the official approval from your city that you're allowed to do the work. An inspection is the city's check that the work was done correctly and safely after it's finished. You get the permit before you start; the inspection happens after you're done.

What should I do if I start a replacement and get stuck?

Take a photo of where you are, turn off the water or power, and call a contractor. Tell them you've started and describe what you've done so far. They can usually finish the job faster than starting from scratch, and you'll only pay for the work that's left.

How do I know if the new part is the right size?

Bring the old part with you when you shop, or write down the brand, model number, and measurements. If you're ordering online, check the return policy. Most retailers let you return unused parts within 30 days, so you can buy it, try it, and return it if it doesn't fit.