All About Indirect Drain(s) – Serious Stuff

Non Freeze Discharge

Non Freeze Indirect Drain

Proper Indirect Vent

Proper Indirect Drain

Improper Direct Vent

Improper Indirect Drain

Indirect Drains 

The image on the left shows an indirect drain going through a building wall to the exterior, this type of drain may go into a septic system, dry well or a municipal storm sewer. 

In the center image we see how a proper "Indirect Drain" can be set up, there should be a minimum of 1.5" of space between the discharge end of the hose to the top of the indirect vent funnel.  This is to prevent any back up water from being sucked back into the system by the discharge hoses, in the event of a change in water pressure. 

The image on the right shows how this homeowner nearly got it right, but the end of  discharge hoses is too close to the sewer intake. They need to be elevated at least 1.5" to prevent flow back in the event that there should be a change in water pressure. 

Residential Water Softener Drain installation tips

Reprint of an article posted July 29th by Creg Reyneke

There are very simple reasons why a water treatment system must never be connected directly to a sewer pipe:

Consider a water treatment system installed with a direct drain connection to the sewer system, that is a cross connection. If, during the regeneration cycle, there is a fire in the vicinity. What would happen if the firemen’s pumping equipment creates such a strong demand for water that suction occurs and it actually causes water to flow from the house back into the main line? Actually, if the suction were strong enough, some fluid from sewer pipes might be drawn back through the water treatment system and back out into the water supply lines. The danger is that sewage containing potentially pathogenic organisms could then be introduced into the water supply.

Obviously, the public health and the private welfare of your household must be at the uppermost consideration in the mind of the installer at all times. This is why the air gap rule, must always be followed, for drainage installations.

A softener drain line must not be connected directly to the waste system, but must be emptied into a laundry tray, floor drain, or properly trapped special outlet, preserving an air gap of at least two times the diameter of the drain line, but in no case less than 1-1/2″ above the top of the receptacle used. The greater of two and a half times the diameter of the equipment’s indirect drain or 1-1/2″ is the minimum air gap for whole house (point-of-entry) water treatment equipment. The greater of 2.5 times the equipment effective drain line diameter, or one inch; is, allowed for point-of-use equipment. In addition, the end of the drain line should be secured so that there is no chance that it can become immersed in waste fluids.

Be sure to study and follow the equipment manufacturer’s installation instructions. They will specify drain line size. If the proper size is not provided, the unit may not be properly backwashed.

Type Of Drain Required

A laundry sink or any other sink can serve satisfactorily as an emptying place, for the drain line, but it’s always best to discharge to the sewer whenever possible.

A trap installed in a waste line will also suffice, providing there is a proper air gap or vacuum breaker between the tap and the drain line from the softener.

A funnel arrangement may also be advantageously used in such an installation. A floor drain may also be used if it is out of the way of traffic. Rigid pipe should be used and positioned so that the minimum air gap cannot be reduced by moving the pipe. When the water treatment system is supplied with flexible drain line material, the drain must be tightly secured in the correct position to avoid deliberate or accidental movement.

Some units provide an overflow drain line, for the regenerant container. Such a line should be run to a floor drain. It must run by gravity feed to a lower drain.

Never EVER install, a drain, like this:


It gets worse (at the same installation):


This entry was originally posted by Greg Reyneke; Greg Knows Water, on Thursday, July 29th, 2010 at 9:33 pm and is filed under Tutorials.