Greywater conversations usually begin with clothes washing machines and showers, which are surely the most abundant greywater families are producing from their homes.  However, there are hidden greywater opportunities worth noting lurking around your home that  are quite accessible.  Namely, AC condensate, water heater condensate, and whole house filter flushes (softeners, RO, etc)

Condensate

There are a couple sources of condensate around homes.  First is obvious: AC units.  However, there are also minisplits, some heaters, and some water heaters that create condensate.   In San Diego, AC use varies depending on the type of home and whether it is inland or coastal.  Estimates place AC condensate production around 5 gallons per day.  The new heat pump hybrid electric water heaters function by pulling warm air in to help heat the water, which produces cool air and condensate (1-2 quarts a day).

Typically, we we are walking around your home, we notice 1/2″ or 3/4″ pvc pipes sticking straight out of the wall about 12″ above the ground or elbowing down and terminating just above the ground.  There are other pipes that do this also like water heater flush lines and water heater tray drains.  Sometimes, accessing this water is a little more complicated as these pipes are located in a crawlspace, or there is a small metal tube directly exiting the AC unit and tying back into the house wall.  Sometimes there is a conduit channel running down the wall of the house which is housing a condensate line.

Often water heaters and whole house filters are located in garages or near laundry rooms, so combining these pipes with the Laundry Greywater pipes is a great option to get the water out to the yard for distribution to plants.

It is important, when tying these lines out to keep two things in mind:

1. you will want to install a swing check valve on the condensate line so that water can drain out of the condensate line, but laundry water (under pressure) cannot enter the heater or AC line
2. Condensate relies on gravity to drain, so it’s important you don’t have pipes routed uphill

Another interesting way to use your condensate, especially if it is coming from up high, may be to drain it into your rainwater tank, to keep refilling your tank during the summer months as shown by the smaller pipe coming into the tank from the left in the picture below.

Whole House Filters/Water Softeners

There are a wide variety of whole house filters on the market, some of which produce “greywater” and some of which do not.  Most filters that include a large cannister have the ability to “self-clean”.  This happens once every week or two and generally produces between 20-30 gallons per flush.

Things to note:

• water softeners rely on salt. Salt is not awesome for your soil.  If you can replace Sodium chloride with potassium chloride as your salt, this may be a better option for you to use as greywater
• Reverse Osmosis generally produces A LOT of waste water.  The newer, more efficient ones use 1 gallon per gallon of clean water.  Typically these are used more for drinking water than whole house.  This water is fine for your garden, however it does have a higher concentration of salts and minerals, so healthy soil is important as well as occasional rainwater flushes in the soil.
• make sure to put a swing check valve on the filter line to prevent laundry water from going back into the filter
• You may need to be strategic about your tie-in location or ALSO put a swing check valve on the laundry line since the filter flush lines are pumped and you don’t water that water going back into the washing machine.

Tying this water in with your laundry line is a great way to get extra bang for your buck by using all the trenching and pipes to distribute this water throughout your distribution area.  You’ll want to make sure you account for the extra water by spreading it further than you would with just your weekly laundry volume.  Eg:  if you are doing 4 loads of laundry a week in your top load washer, you are producing about 100 gallons of greywater (enough for about 4 fruit trees).  By adding your filter flush water you may decide to distribute to an extra tree, or add some companion plants to your orchard!

The added benefit of these additional sources of water to your laundry greywater line is you move this water away from your foundation.  Water pooling near your foundation consistently can cause problems either with foundation cracking or pooling water in your crawlspace.  It’s important to keep water 5-10 feet away from your foundation.  This means limiting irrigation to small amounts of drip irrigation for drought tolerant plants around the house.  Send the rest of this fantastic resource further away to support shade, food, pollination, beauty, and abundance!

Sign up for a consultation with us to learn how to use your greywater resources to keep your garden thriving!