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INSTALLATION STANDARDS · CONDENSATE

How Honest Fix Installs a Condensate Drain

Every air conditioner pulls water out of your air, and every high-efficiency furnace makes water as it cools its exhaust. That water has to go somewhere. Honest Fix installs every condensate line to a written standard: sloped, supported, trapped, and protected by a safety switch. This page is that standard, published in full, so you can hold any contractor to it. Ours included. 

Published from our Installation Handbook · Reviewed by Alex Largent · 100% satisfaction, no exceptions 

High-efficiency furnace installation with condensate drain and disconnect, basement setting.

Water has to run downhill, the whole way

Horizontal PVC gets proper slope and a support every four feet, because unsupported PVC sags as it ages and a sag becomes an air trap. 

Every coil gets an overflow switch

A safety switch sits in the secondary drain port on every coil and air handler, so a blocked line shuts the system down instead of soaking your ceiling.

Where the water goes matters

The line never terminates on a walkway, porch, or roof in freezing weather, and never where the water runs back toward your siding or foundation. 
THE HONEST FIX CONDENSATE STANDARD

Four Things a Condensate Line Has to Get Right

Your condensate line is the least glamorous part of your system and one of the most common sources of water damage in a home. It is also the part a rushed installer is most likely to shortcut, because it is buried behind the equipment where nobody looks. Here is what Honest Fix requires on every installation. You are welcome to check ours against it. 

Slope and support

Every horizontal PVC condensate line runs at ¼ inch of fall per foot, with a support at least every four feet. PVC bows over time wherever it is unsupported, and a bow creates an air trap that stops the line from draining. Cuts are made straight so the joint seats fully inside the fitting.

Diagram of a correctly sloped condensate line: one-quarter inch of fall per foot, supported every four feet.

The trap and the air tee

Every evaporator coil and air handler gets a properly oriented condensate trap, and the pipe or cap in the top of the tee is never glued, because that fitting has to open for service. A gas furnace will usually need an air tee as well, and which one comes from that furnace's installation instructions, not from habit. When a furnace and a coil share a drain, the furnace line ties in downstream of the coil trap, on a downward run.

Diagram of correct condensate trap orientation with a do-not-glue callout on the open tee.

The safety switch

Mechanical code requires overflow protection on cooling coils and air handlers, and a float-style safety switch is the method we install. It sits in the secondary drain port, and if the primary drain blocks, the switch shuts the system off before water backs into your ductwork. Where a condensate pump is used, the pump's own safety switch interrupts the control signal at the board, and the vinyl drain line is clamped to the pump fitting.

Diagram of an overflow safety switch in the secondary drain port that shuts the system off if the drain backs up.

Where it ends

The line does not terminate on a walkway, a porch, or a roof where it can freeze, and it does not get a 90-degree elbow at the termination. It does not drain into an unconditioned space where it can freeze. And it is placed so the water does not run back toward your siding or drip onto your foundation.

Diagram comparing allowed and not-allowed condensate line termination locations.
WHY THIS ONE MATTERS HERE

In the Upper Ohio Valley, Your Drain Line Works Harder Than Most

River-valley humidity means your system pulls more water out of the air than it would in a drier climate, and it does it for more of the year. A drain line that would get away with a shortcut somewhere else does not get away with it here.

A sagging line stops draining

Unsupported PVC bows as it ages. The bow holds air, the air blocks the water, and the pan fills up behind it. 

A blocked line finds another way out

Without a safety switch, water backs up into the ductwork and the equipment. That is a ceiling repair, not a drain repair. 

A frozen termination backs the whole line up

A line that ends on a porch or a roof, or that runs through an unconditioned space, will freeze. Then it has nowhere to drain. 

A misplaced termination goes after your house

Water running back toward the siding or dripping on the foundation does slow damage you will not notice until it is expensive. 

Field conditions. Final installation details may vary based on manufacturer requirements, local code, home conditions, equipment model, safety constraints, and the written scope of work. Where the manufacturer's instructions and this standard disagree, the manufacturer's instructions win, and your technician follows them. 
CONDENSATE DRAINS

Common Questions

Why is water leaking from my furnace or air handler?

What is the white PVC pipe coming off my equipment?

Why does my drain line have a switch on it?

Do I need a condensate pump?

Where is my condensate line supposed to drain?

My drain line drips outside in the winter. Is that a problem?

How do I know my condensate line was installed right?

Last Updated: November 12th, 2026

Have a Look at Yours

Now you know what a correct condensate line looks like. If yours does not look like this, or you would rather have someone else check, Honest Fix will come out and give you a straight answer. No upsells, no games. 

Air handlers · Evaporator coils · High-efficiency furnace · Ductless head drains · AC repair · The full Installation Standard

Honest Fix service van parked outside a home in Steubenville, OH.