Skip to main content

Secure Connections and Turn on Water — Install the New Supply Line

Beginner

Part of project

How to Replace a Toilet Water Supply Line · Step 3 of 4

Helpful?

In this video

From underneath the tank, screw the new plastic locknut onto the shank of the fill valve and hand-tighten it securely. Do not use pliers, as over-tightening can crack the plastic. Next, reattach the water supply line to the bottom of the new fill valve, also hand-tightening it firmly. Once all connections are secure, slowly turn the water shut-off valve counter-clockwise to turn the water back on. As the tank fills, check for any leaks at the supply line connection and the locknut.

Goal: Connect the water supply and check for initial leaks

  • Hand-tighten only. Using a wrench on the plastic locknut or supply line connector can cause cracking and lead to flooding.

Used in this video

  • Towel (Towel Material: Cotton)Drying connections to make leak detection easier.
1.3K views405 minutes
replumb

719K subscribers

View Channel

FAQs

How difficult is it to replace a toilet supply line, and how long does it usually take for a beginner?

This is a beginner-level plumbing project, typically taking only 15-30 minutes to complete. The most time-consuming part is often ensuring all connections are leak-free. The cost is usually just for the new supply line, which is quite inexpensive.

Why is a braided stainless steel supply line recommended over other types, like plastic or standard polymer lines?

Braided stainless steel lines offer superior durability and burst resistance compared to older plastic or non-braided polymer lines. They are less prone to kinking and cracking over time, providing a more reliable and long-lasting connection to your toilet. This minimizes the risk of catastrophic water damage from a burst line.

What should I do if I find a leak after installing the new supply line and turning the water back on?

First, immediately turn off the water supply again at the shut-off valve. Gently tighten the connections a small amount (about a quarter turn) with your adjustable wrench. Ensure the rubber washers or cones are properly seated and not pinched. Avoid overtightening, as this can damage the fittings or line.

What if the water shut-off valve behind the toilet is old, stuck, or won't completely stop the water flow?

Do not force a stuck valve, as it could break and cause a larger leak. If the valve doesn't fully shut off the water, you'll need to turn off the main water supply to your house before proceeding. This might also be a good opportunity to replace the old shut-off valve itself, as a separate, slightly more involved project.

Transcript
Hide

Alright, that's tucked away nicely now, let's attach this log nut. Make sure this log nut is tight, but there's no need to use pliers, hand tie on all these parts as all you want. Now we'll reattach this to the pyline and same with this, just hand tight. Alright, looks like everything up here is nice and tight, that is good, and then we'll check and make sure this is tight one more time and then we'll turn on the water. And while we're down here, we'll go ahead and check for any obvious leaks and everything looks good.

Auto-generated transcript. May contain errors.