Category: Plumbing

Short answer: If the toilet is not clogged but only flushes all the way when you hold the handle, the flapper is closing too soon (chain too long or a waterlogged flapper). If the tank water level is low, adjust the fill valve. Mineral-clogged rim jets and a blocked vent also cause weak flushes.

Quick diagnosis

What you notice	Most likely cause	What to check	Call a pro?
Flushes fully only if you hold the handle	Chain too long or flapper closing early	Shorten the chain slack	Rarely
Water level in the tank is low	Fill valve set low or supply valve partly closed	Mark the water line; adjust	Rarely
Bowl drains slowly, then flushes weakly	Partial clog in the trapway	Plunge with a flange plunger	If it will not clear
Weak flush, gurgling in other drains	Blocked vent	Listen to sinks while flushing	Yes
Weak swirl, stains under the rim	Clogged rim jets	Look under the rim with a mirror	Rarely

Adjust the chain and flapper

With the lid off, the chain should have only a little slack when the flapper is closed. Too much slack and the flapper drops before the tank empties. An old flapper that has become waterlogged also closes too early and should be replaced.

Raise the tank water level

The water should reach about an inch below the top of the overflow tube. If it is lower, adjust the float or check that the shutoff valve is fully open.

Partial clogs and vents

A toilet that drains slowly before flushing usually has a partial clog: use a flange plunger or a closet auger. If several fixtures gurgle when you flush, the vent may be blocked; see clog deep in the drain pipe.

When to call a professional

• Plunging and an auger do not help.
• Other drains back up when you flush.
• The toilet is cracked or leaks at the base.

What it usually costs

Chains and flappers cost a few dollars. Toilet repair by a plumber runs about $100 to $300 (HomeGuide, 2026).

Frequently asked questions

Why does my toilet only flush if I hold the handle down?

The flapper closes before the tank empties, usually because the chain is too long or the flapper is worn.

Why is my toilet tank water low?

The fill valve float is set too low, or the supply valve is partly closed.

Related problems

• Toilet keeps running
• Clog deep in the drain pipe
• Sewer smell in the bathroom

Sources

• U.S. EPA WaterSense: Fix a Leak Week
• HomeGuide: Plumber cost per hour (2026)

This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.

Short answer: A single loud bang right when water shuts off quickly (washing machine, dishwasher, ice maker, a lever faucet) is water hammer: the moving water stops suddenly and the shock travels through the pipes. Common fixes are water hammer arrestors near the appliance valves, securing loose pipes and lowering excessive water pressure.

Quick diagnosis

What you notice	Most likely cause	What to check	Call a pro?
Bang when the washer or dishwasher valve closes	Water hammer from fast-closing solenoid valves	Notice if the bang matches the valve	Often for arrestor install
Bang when you shut a faucet quickly	Water hammer	Close the faucet slowly and compare	Sometimes
Rattling as water runs	Loose pipes against framing	Look for unsecured pipes in the basement	Sometimes
Banging from the water heater	Sediment in the tank	Listen at the tank while heating	See water heater guides
Noise everywhere and high pressure	Pressure too high or failing PRV	Test pressure with a gauge	Often

What water hammer is

When a valve closes suddenly, the moving water stops and creates a pressure surge that can make pipes bang. This Old House describes a water hammer arrestor, a small cushioned chamber installed near the valve, as the standard fix. Manufacturers such as Watts make arrestors for washing machine boxes and fixture supplies.

How to reduce it

• Install water hammer arrestors at the washing machine and dishwasher supplies.
• Secure loose pipes with straps so they cannot slap against joists.
• Check the house water pressure; very high pressure makes hammer worse, and a pressure-reducing valve may need adjusting.
• Older homes may have air chambers that have filled with water; draining the system can restore them temporarily.

When to call a professional

• The noise is violent or started suddenly.
• You see leaks at fittings.
• Water pressure is very high or the PRV needs service.
• Arrestors need to be added inside walls.

What it usually costs

Screw-on arrestors for a washing machine cost a modest amount at hardware stores. Installing arrestors in walls or adjusting a PRV is plumber work at $45 to $150 per hour (HomeGuide, 2026).

Frequently asked questions

Is water hammer dangerous?

Repeated pressure spikes can loosen fittings and damage valves and appliances over time, so it is worth fixing.

Why do my pipes bang when the toilet fills?

A fill valve that shuts off quickly can cause hammer, especially with high water pressure.

Related problems

• Low water pressure in the whole house
• Water heater leaking
• Toilet keeps running

Sources

• This Old House: How to quiet pipes with a water hammer arrestor
• InspectAPedia: Water hammer pipe banging noise FAQs
• HomeGuide: Plumber cost per hour (2026)

This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.

Short answer: If the rest of the house is fine, the problem is at the fixture. Unscrew and clean the aerator or showerhead, make sure the shutoff valves under the sink are fully open, and if only the hot side is weak, suspect the cartridge or the water heater. Whole-house weakness is a different problem.

Quick diagnosis

What you notice	Most likely cause	What to check	Call a pro?
Kitchen faucet weak, others fine	Clogged aerator	Unscrew the tip and look for debris	Rarely
Weak after plumbing work or a main shutoff	Debris in the aerator or cartridge	Clean the aerator	If cleaning does not help
Weak on hot only	Cartridge, hot shutoff valve or water heater sediment	Check the hot shutoff under the sink	Sometimes
Shower weak, sinks fine	Clogged showerhead or flow restrictor	Remove and soak the head	Rarely
Pull-down faucet weak	Kinked hose or check valve	Look under the sink at the hose	Sometimes

Clean the aerator

1. Close the drain so small parts do not fall in.
2. Unscrew the aerator from the faucet tip (wrap it with tape if you use pliers).
3. Rinse out sand and mineral flakes; soak in vinegar for scale.
4. Reinstall and test.

Check the shutoff valves

The two small valves under the sink should be fully open (turned counterclockwise). After any repair, someone may have left one partly closed.

Showerheads

Mineral scale clogs the nozzles. Remove the head and soak it in vinegar, or rub the rubber nozzles to break scale loose. Low-flow heads are restricted by design; that is normal.

When to call a professional

• Cleaning the aerator and opening valves does not help.
• The faucet cartridge needs replacing and you are not comfortable doing it.
• The problem spreads to other fixtures.

What it usually costs

Cleaning an aerator or showerhead is free. A plumber typically charges $45 to $150 per hour plus a call-out fee (HomeGuide, 2026).

Frequently asked questions

Why is my kitchen sink water pressure low but not the bathroom?

The cause is at the kitchen faucet itself: a clogged aerator, a partly closed shutoff or a kinked pull-down hose.

Why is only the hot water pressure low?

A partly closed hot shutoff valve, a worn faucet cartridge or sediment in the water heater are the usual causes.

Related problems

• Low water pressure in the whole house
• No hot water
• Pipes banging (water hammer)

Sources

• Denver Water: Low water pressure
• HomeGuide: Plumber cost per hour (2026)

This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.

Short answer: Lift the tank lid and look. If water is spilling into the overflow tube, the fill valve or float is set too high. If not, the flapper is leaking water into the bowl. The EPA recommends a simple dye test: a few drops of food coloring in the tank, wait 10 minutes, and color in the bowl means a leak.

Quick diagnosis

What you notice	Most likely cause	What to check	Call a pro?
Water spills into the overflow tube	Float set too high or fill valve failing	Lower the float; see if it stops	If the valve keeps running
Refills by itself every so often (phantom flush)	Leaking flapper	Dye test	Rarely
Runs after you changed the flapper	Wrong size flapper, chain too tight	Check the chain slack and flapper size	Sometimes
Runs even with the float up	Fill valve seal worn	Replace the fill valve	If not comfortable
Hissing and never fills fully	Fill valve or low supply	Check the supply valve is fully open	Sometimes

Do the dye test

The U.S. EPA’s WaterSense program says to put a few drops of food coloring in the tank, wait 10 minutes without flushing, and check the bowl. If color appears, the toilet is leaking. Flush right away so the tank does not stain.

Fix a leaking flapper

The EPA notes that a worn flapper can leak thousands of gallons a year without obvious signs, and recommends checking it periodically and replacing it at least every five years. Take the old flapper (or a photo) to the store to match the size, and leave a little slack in the chain.

Adjust or replace the fill valve

The water level should sit about an inch below the top of the overflow tube. Adjust the float (a screw on a float arm, or a clip on a cup-style float). If water still runs into the overflow with the float lowered, the fill valve is worn and should be replaced.

When to call a professional

• The tank or bowl is cracked, or water leaks at the floor.
• The shutoff valve under the tank will not close or leaks.
• You replaced the parts and it still runs.

What it usually costs

A flapper or fill valve costs a few dollars to about $25 at a hardware store. HomeGuide (2026) lists toilet repair by a plumber at about $100 to $300.

Frequently asked questions

How much water does a running toilet waste?

It can waste thousands of gallons a year. The EPA counts toilet leaks among the most common household leaks.

Why does my toilet run on and off by itself?

A leaking flapper lets the tank slowly drain into the bowl until the fill valve turns on to refill it.

Related problems

• Toilet won’t flush all the way
• Sewer smell in the bathroom
• Low water pressure in the whole house

Sources

• U.S. EPA WaterSense: Fix a Leak Week
• Minnesota Pollution Control Agency: Toilet leak dye test card (PDF)
• HomeGuide: Plumber cost per hour (2026)

This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.

Short answer: If every tap in the house is weak, look at the supply: a main shutoff valve that is not fully open, a failing pressure-reducing valve (PRV), corroded galvanized or old service pipes, a hidden leak, or a problem on the utility side. If it happened suddenly, ask your neighbors and call your water utility first.

Quick diagnosis

What you notice	Most likely cause	What to check	Call a pro?
Sudden drop, neighbors too	Utility work or main break	Ask neighbors; check the utility’s outage page	Call the utility
Sudden drop, only your house	Main valve partly closed, PRV failure, leak	Check the main valve and the meter	Often
Weak for years, older home	Corroded galvanized or old service line	Ask when the pipes were replaced	Yes
Hot water only is weak	Water heater shutoff or sediment	Compare hot and cold	Sometimes
Weak only with a well	Well pump or pressure tank	Check the pressure gauge on the tank	Yes

Check these first

1. Ask a neighbor or check your water utility’s website for outages or main breaks.
2. Make sure the main shutoff valve (where the line enters the house) is fully open.
3. Find the pressure-reducing valve, usually a bell-shaped valve right after the main shutoff. Many homes have one; if it fails, pressure can drop or spike.
4. Turn everything off and watch the water meter. If it still moves, you probably have a leak, which also lowers pressure.

Old pipes and the service line

Denver Water explains that low pressure in older homes is often reduced flow caused by mineral buildup narrowing old lead and galvanized service lines, and that the service line from the street is the property owner’s responsibility. The permanent fix is replacing the line, done by a licensed plumber or contractor.

Pressure-reducing valve (PRV)

A PRV keeps city pressure at a safe level for your home. When it wears out, pressure can drop or become erratic. Adjusting or replacing a PRV should be done with a gauge, and many homeowners hire a plumber for it.

Homes on a well

With a private well, whole-house low pressure usually points to the pressure switch, the pressure tank or the pump. A gauge on the tank shows the cut-in and cut-out pressures; a well contractor or plumber can diagnose it.

When to call a professional

• The meter moves with all water off (possible leak).
• Pressure dropped suddenly and the utility says there is no problem on their side.
• You have old galvanized or lead pipes.
• The PRV needs adjustment or replacement.
• A well system is losing pressure.

What it usually costs

Plumbers typically charge $45 to $150 per hour plus a call-out fee (HomeGuide, 2026). Replacing a service line or repiping is a major job; get written quotes.

Frequently asked questions

Why did my water pressure suddenly drop in the whole house?

Utility work, a main break, a partly closed main valve, a failing pressure-reducing valve or a leak are the most common causes.

Who is responsible for low water pressure?

The utility handles the water main and meter in most cities; the service line and plumbing on your side are usually the owner’s responsibility. Check your utility’s policy.

Related problems

• Low water pressure in one faucet or shower
• No hot water
• Pipes banging (water hammer)
• Toilet keeps running

Sources

• Denver Water: Low water pressure
• City of Phoenix Water Services: General service issues
• HomeGuide: Plumber cost per hour (2026)

This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.