All softeners have a dlfc drain line flow control it controls limits the max gpm flow to drain.
Water softener drain field.
Well we have some good news.
According to most plumbing codes a water softener drain line must not be connected directly to the household waste system.
The discharge from a water softeners regeneration will damage my septic system or drain field in studies conducted by scientists in the late 1970 s at the university of wisconsin it was confirmed that salt brine discharge from water softeners caused no problems in the operation of typical anaerobic or newer style aerobic home treatment.
This is to prevent non potable water from flowing backwards possibly mixing and contaminating potable drinking water.
If local code allows i would recommend diverting the softener backwash water to another location outside of the septic system.
This assumption was based on agricultural studies of irrigation systems with a high sodium content.
The discharge was no more or less than that of any other household water using appliance.
Most won t flow more than 2 7 gpm.
The max gpm dlfc for a large residential softener would not be more than 5 gpm.
By code water softeners must be emptied into a laundry sink floor drain sump hole 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.
We have seen a septic drainfield completely flooded by a water softener that stuck in it s backwash cycle.
A study commissioned in 2012 by the water quality research foundation reported that brine discharge from well operated water softeners 50 gallons per regeneration showed no overflow.
This causes two problems.
If you hear water running continuously in your drain you should track down the source to a leaky toilet tank faucet or malfunctioning water softener etc.
A water softener does not pose a problem for your beloved septic system.
One concern with water softeners and septic systems is that the amount and flow rate of the brine discharge can overflow a septic tank and back up the drain field.
There s also the concern that the hardness ions can disrupt your drain field s absorption.
Watch for malfunctioning water softening equipment.
This is a large surge load which can upset the settling process in the tank.
A backwashed or regenerated filter can go to 10 gpm.
Finally it was feared that the salt brine produced by the softener would hamper the drainage field s ability to absorb water and affect bacterial populations.
When the water softener resin is backwashed two or three times a week concentrated brine enters the wastewater stream as a slug of 38 to 112 gallons each backwash cycle.
