What Type of Tubing for Water Softener Drain? The Complete Guide

Hey there! If you‘re researching what type of tubing to use for your water softener drain, you‘ve come to the right place. Properly installing the drain line is crucial for your softener to function properly and last a long time. As a home improvement expert with over 10 years of experience in plumbing and renovations, I‘ve worked on all kinds of water softener drain line projects. In this comprehensive guide, I‘ll walk you through everything you need to know about picking the right tubing and configuring the perfect drain setup.

Why Do You Need a Drain Line?

The drain line carries away the salty brine solution from the softener after it finishes a regeneration cycle. This is the process where it flushes out the hardness-causing mineral buildup and recharges the resin beads. Without a drain line, the brine would back up inside the system and cause all kinds of problems like leaks, corrosion, and overflow. No bueno!

Trust me, taking the time to install a proper drain line will save you headaches down the road. Let‘s look at what type of tubing you should use.

Tubing Material Options

There are a handful of different tubing types that are suitable for water softener drains:

Polyvinyl Chloride (PVC)

PVC is a lightweight plastic piping that‘s extremely common for household plumbing and drainage applications. It‘s economical, easy to install, and can handle the flow rates of most residential water softeners.

Cost: PVC tubing is one of the most inexpensive options, usually between $0.20-$0.60 per foot.

Temperature Rating: PVC tubing is approved for cold water only. The maximum temperature it can withstand is 140°F. Do not use it for hot water softener drains or you‘ll risk deforming the pipe.

Sizes: 1⁄2” or 3⁄4” PVC tubing will work for most standard household softeners up to about 25-30 gallons per minute drain flow.

Installation: PVC tubing uses slip-fit connections with solvent cement and primer to join sections. The solvent welding process is straightforward. Just make sure the connections are fully cured before pressure testing the drain line.

Pros

• Inexpensive
• Easy to install and modify
• Readily available

Cons

• Not highly chemical resistant
• Not suitable for hot water
• Can become brittle over time

Overall, PVC is a great choice for water softener drain lines on a budget. It‘s good enough for most residential applications.

Polyethylene (PE) Tubing

Like PVC, polyethylene tubing is also an affordable plastic piping. It‘s extremely flexible, chemical resistant, and commonly used for supplying ice makers, humidifiers, and RO systems.

Cost: Slightly more than PVC but still very affordable, usually between $0.30 – $0.80 per foot.

Temperature Rating: PE is rated for up to 100°F continuous use. Okay for warm water but don‘t use for hot water lines.

Sizes: Standard 1⁄2” or 3⁄4” tubing works for most softeners.

Installation: Uses push-fit insert fittings for super easy connections. Can be installed by anyone without solvent cement.

Pros:

• Extremely flexible
• More chemical resistant than PVC
• Easy push-fit connections
• Low cost

Cons:

• Can get algae buildup over time
• Not suitable for hot water
• Requires more frequent cleaning than PVC

Polyethylene tubing is another solid choice for water softener drains. It‘s a great DIY-friendly option.

CPVC Tubing

CPVC or chlorinated polyvinyl chloride tubing is like PVC but specially treated to withstand hot water up to 200°F. This makes it perfect for softener drains that may have warmer discharge.

Cost: Approximately 2-3 times more expensive than PVC. Around $1.00 – $2.00 per foot.

Temperature Rating: Rated for temperatures up to 200°F. Can withstand hot water discharge.

Sizes: 1⁄2”, 3⁄4”, and 1” sizes available.

Installation: Uses solvent cement joining process just like PVC tubing. Requires primer, cleaner, and glue before assembly.

Pros:

• Handles hot water discharge
• Very durable material
• More corrosion resistant than PVC

Cons:

• More expensive than PVC or PE tubing
• Not quite as flexible or easy to install as other options

CPVC is the ideal tubing if you need to handle hotter drainage above 140°F. It has better heat tolerance than plastic options.

Stainless Steel Tubing

For extremely high heat and very corrosive brine discharge, stainless steel may be the most heavy duty option. It withstands essentially any temperature and lasts for decades.

Cost: Most expensive option at $4.00+ per foot for residential tubing sizes.

Temperature Rating: Can withstand well above 200°F.

Sizes: 1⁄2”, 3⁄4”, and 1” available for home softeners.

Installation: Requires skill to precisely cut and join sections. Usually installed by a professional.

Pros:

• Withstands any temperature
• Extreme corrosion resistance
• Very long service life

Cons:

• Expensive upfront cost
• Difficult for DIY installation
• Less flexible than plastic tubing

Stainless steel tubing is overkill for many homes but it‘s the ultimate option for large commercial systems with very high heat or corrosion levels.

What Size Tubing is Needed?

Choosing the correct diameter of tubing is key to prevent flow restrictions. Here are the general size guidelines based on your softener‘s drain line flow rate:

• Up to 12 GPM units – 1⁄2” tubing
• 12 to 25 GPM units – 3⁄4” tubing
• 25 to 40 GPM units – 1” tubing

Refer to your water softener model‘s specs to get the drain line GPM flow rate. If in doubt, go a size up – it‘s better to have a slightly oversized drain than one that‘s too small.

How Should You Route the Drain Line?

You have some options when it comes to routing the drainage from your water softener system:

Draining Into a Floor Drain

If there‘s a floor drain conveniently located near the water softener, this can be the easiest option. Just run the tubing directly into the drain inlet. Be sure the drain size can handle the GPM from the softener.

Draining Into a Laundry Sink

Tying the drain line into the sink for your washing machine is another common setup. Depending on the relative elevations, you may need to install a high loop to prevent possible backflow into the softener.

Draining Into Main Sewer Line

It is possible to route the drain line to your main sewer outlet or septic tank connection, although this often requires installing a backflow prevention device. Consult your plumber on this option.

Draining Outside

Running the tubing through the wall to drain outside is fine as long as you have somewhere for the brine to fully disperse away from the house foundation. Make sure to add an air gap fitting.

Draining Into a Dry Well

For outside drainage, a gravel-filled dry well allows the brine to collect and dissipate down into the ground. It keeps the salty discharge completely away from your home‘s foundation.

Choose the drainage point that‘s most convenient for your particular water softener setup.

Tips for Proper Installation

Once you‘ve selected the right tubing type and size, follow these best practices when installing the drain line:

• Maintain a downward pitch of at least 1⁄4” per foot to promote proper drainage flow.

• Minimize any sharp 90 degree bends, use large radius elbows whenever possible for smooth turns. This prevents flow restrictions.

• Secure the tubing with clamps/hangers every 4-5 feet on horizontal runs to prevent sagging.

• Insulate any exterior drain line sections to prevent freezing in cold climates. Heat tape can also be used.

• Use primer, cleaner, and solvent (for PVC/CPVC) or insert fittings (for PE) to join tubing segments for leak-free connections.

• If connecting into sewer/septic lines, install an approved backflow prevention device to code.

Correct installation is just as important as using the right tubing material. Taking the time to do it right will pay off with years of trouble-free operation.

When Do You Need a Condensate Pump?

If the water softener drain termination point is located above the softener, such as in a second floor laundry tub, you most likely need to add a small condensate pump. This helps pump the brine waste up and out to reach the elevated drain connection.

Condensate pumps suitable for water softener drains range from 1/8 HP to 1/4 HP and pump around 2-3 gallons per minute. Make sure to size the pump based on your softener‘s expected drain line flow rate.

Install it in the drain tubing run at a low point where water can gravity flow into the sump. Then it will pump upward from there. Follow the manufacturer‘s instructions for proper setup and wiring.

Installing an Air Gap Fitting

An air gap is a must-have when draining into a sink or sewer line at a higher point than the softener. It prevents potentially hazardous backflow of wastewater.

Simply install an air gap fitting at the discharge end of the drain tubing according to the manufacturer instructions. This creates a physical air space between the drain line and the plumbing connection, allowing discharge flow while preventing siphoning.

Maintaining the Drain Line

Like any plumbing, the water softener drain line needs occasional maintenance:

• Inspect along the full length of tubing to check for leaks, damage, or clogs

• Flush drain lines with bleach or other disinfectants to prevent algae/bacterial buildup

• Clean out debris from exterior discharge outlets

• Ensure condensate pumps are functioning properly if installed

• Check for obstructions in air gaps or backflow preventers

Taking a few minutes for routine drain line maintenance will keep everything flowing smoothly for years.

Does Drain Water Harm Septic Systems?

This is a common question for homes on septic systems. The good news is that standard water softener backwash will not directly harm or damage a septic tank when drained into it.

However, it is still advisable to avoid draining directly into the septic for a few reasons:

• The high volumes of brine/backwash water can potentially overload or overfill the septic tank.

• The increased sodium content may throw off the helpful bacteria balance in the septic system over time with regular softener recharges.

• Any resin beads or sediment discharged could gradually build up inside the septic tank.

The best practice is to route the softener drain away from the septic tank if possible. Connecting to a separate dry well or dispersal field is ideal to keep the salty water completely separated from the septic system.

If you must tie into the septic tank, try to install a brine mixing tank to dilute the mineral concentration first, and limit recharges to only when truly needed. Consulting a wastewater specialist is also a good idea when integrating a softener with your septic system.

Will Softeners Damage Plumbing?

This is a very common concern for those new to water softeners. But rest assured that water softeners themselves do not damage pipes or plumbing when properly installed and maintained.

The water softening process simply switches out the hard calcium and magnesium minerals in the water for softer sodium ions. This treated water flowing through your pipes is no more damaging than regular unsoftened water.

That said, there are a few caveats:

• If the system is not recharging and re-filling with salt regularly, the water could revert back to untreated hard water which then allows scale buildup in pipes over time.

• Salt tanks need occasional cleaning to remove sediment buildup. Excess sediment getting into pipes could cause abrasion damage.

• Avoid excessive salt dosing. Water that is too salty can corrode plumbing and damage appliances.

So be sure to keep your softener well maintained with regular salt refills and sediment cleaning, and avoid over-salting. As long as you do this, your plumber will be happy!

Is It Okay to Drain into My Garden?

This is not advised. While the sodium and minerals from water softener backwash are not directly toxic, the concentrated salt content can damage plants, soil structure, and beneficial microbial life in the garden when applied heavily.

Repeatedly draining the brine into one area can cause salt burn on vegetation and create challenges restoring soil health. Instead, it’s best to drain and disperse the backwash away from any landscape or gardens where possible.

In Closing

I hope this guide has helped explain the drain line options for your water softener. The key takeaways are:

• Use 1⁄2” or 3⁄4” tubing size to match your softener’s flow rate

• PVC, PE, or CPVC tubing materials all work well and are easy to install

• Configure the drain line with an air gap into sewer, septic, or an exterior dry well dispersal point

• Maintain the drain tubing to keep it clear of obstructions

Installing the proper drain line helps ensure your water softener can operate properly for many years to come. Let me know if you have any other questions!