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Dishwasher Water supply line: What It Does and Signs It's Failing

The braided or copper line that brings hot water from the shutoff valve under the sink to the inlet valve on the dishwasher. Bosch (AquaStop) and Miele (Waterproof) add leak protection on top: when it detects a leak, the machine stops and pumps the water out. Models sold with an AquaStop-type inlet hose make that hose part of the system.

How it works

House water pressure pushes water through the line whenever the inlet valve opens. On most US installs a brass 90-degree elbow threads into the inlet valve and the supply line connects to that.

Signs it is failing

• Water under the dishwasher or in the sink cabinet
• A slow fill or a no-fill code with the shutoff open
• A crushed or kinked line behind the machine
• Corrosion or drips at the elbow fitting
• A leak-protection code right after an install

Leak and drip-tray codes on a new install are often a loose fitting at the inlet valve, and fill codes often trace back to a pinched line.

Can you replace it yourself?

Close the shutoff under the sink and switch off the breaker before loosening anything. Swapping the line is basic plumbing, but you'll have to slide the dishwasher out partway to reach the valve end. Don't reuse old compression ferrules.

Buying the right part

A braided stainless line with the correct dishwasher elbow is the usual choice. Replace a leak-protection inlet hose with the brand's own part so the protection still works.

Error codes linked to the water supply line

• E15Water detected in the base (leak protection)Bosch
• E16 / E17Water can't enter the dishwasherBosch
• E18Water level too lowBosch
• i10Low fill detectedFrigidaire
• H2OLow waterGE
• F8E4Water found in the drip trayKitchenAid
• H2ONo water detectedKitchenAid
• IENot filling with enough waterLG
• F12 / F13 / F15Water inlet blocked or restrictedMiele
• Water inlet fault / Water intake light flashingNot enough water coming inMiele
• F70Waterproof system triggered (leak)Miele
• 4C / 4ENot enough water coming inSamsung
• LC / LELeak detectedSamsung
• F8E1 / H2ONo water detectedWhirlpool
• F8E4Water in the drip trayWhirlpool

Last reviewed 2026-10-19.