Guide To Reusing Water for Gardening

According to the EPA, the average American household uses 300 gallons of water daily. Seventy percent of that water goes toward indoor use like toilet flushing, washing hands, and cleaning clothes. The remaining 30% goes toward outdoor applications like watering the lawn or garden, washing a car, etc. The outdoor percentage is typically much higher in Western and Midwestern states, as more water is needed to keep their lawns and gardens alive. Statistics show that states like Idaho, Utah, and Wyoming use up to 60% more public and groundwater per capita than the national average.

Ultimately, households use a massive amount of municipal water on their lawns and gardens, and many eco-conscious homeowners have begun taking steps to combat this. As a result, water reclamation techniques and conservation efforts have grown in popularity, especially in the Western portions of the U.S. In this article, we’ll go over all major household water recycling techniques and how you can implement them.

What Kind of Water Can You Upcycle for Your Garden?

There are several valuable water systems that you can tap into to obtain water for your plants. Besides using standard fresh water, you can also use captured rainwater, wastewater reuse systems, and reclaimed household water.

Rainwater

Capturing and reusing rainwater is likely the easiest and potentially most effective water conservation technique in this guide. This process uses a capturing system to collect rainwater runoff from your home’s gutters. This water is stored inside a rainwater barrel (sometimes called a water butt) and either saved for later or sent directly to your irrigation system. This method sees varying degrees of effectiveness based upon regionality, as some locations receive much less rainfall than others. For states with high amounts of rainfall, like Ohio, Washington, or Oregon, you can massively cut down on water use with one of these systems.

Wastewater

What is Wastewater?

As clean water comes into your home from the public water supply, household systems, like appliances, sinks, or toilets, will use it, turning it into wastewater. Once used and drained, your home’s plumbing sends wastewater to your sewage system. This water is then sent to a water treatment plant and, through various industrial processes, is cleaned, filtered, and returned to the public water supply. Depending on the wastewater’s level of treatment and local public health regulations, it’s classified as either non-potable or potable water. Water that is once again safe for human consumption is potable, while water that is not safe for human consumption (like sprinkler water) is non-potable.

Different Kinds of Wastewater

Before domestic wastewater hits the water treatment plant, it falls into one of two categories: blackwater and greywater (sometimes spelled gray water or graywater).

Blackwater is the more dangerous of the two household wastewaters, containing hazardous contaminants like human waste or highly caustic chemicals. Due to its contaminated and toxic nature, homeowners should not handle black wastewater, and it should never be recycled or reused outside industrial waste processing facilities. Blackwater comes from toilets, stormwater, sewage systems, and septic tanks.

On the other hand, greywater is less dangerous, coming from appliances, sinks, and bathtubs. While this type of wastewater still contains contaminants, like food particles and detergents, homeowners can handle it as long as they wear equipment like gloves and eye protection. While greywater is unsafe to ingest, it can still be recycled and reused for watering plants.

Household Water

Reclaimed household water is any water that is mostly clean but has been sitting and is no longer preferable (or safe) to consume. These types of water can originate from public water supplies or be leftovers of commercial products. Most water in this category gets poured down the sink or, at best, thrown outside into the lawn. Some types of water in this category include:

  • Unused drinking water
  • Sitting pipe water (cold water from a faucet we ignore as we wait for it to warm)
  • Water used to boil pasta
  • Water for vases of flowers
  • Old coffee

Typically, this water gets poured down the drain, converted into wastewater, and ends up in a sewer, wastewater treatment plant, or some other municipal wastewater system. Instead, you can take advantage of this used water by pouring it directly into your garden or lawn.

How Do You Reuse Water?

Now that we’ve gone over all the different kinds of water you can recycle, let’s go over how to collect, store, and distribute them.

Rainwater Collection

Collecting rainwater is one of the most straightforward and safest water resources. All you have to do is purchase a plastic rain barrel and place it outside when it rains. Rain will fall, be collected in the barrel, and can then be used to water your decorative plants, shrubs, trees, or even gardens.

While having a few rain-catching barrels outside can net you a decent amount of water, this method becomes exponentially more efficient when combined with your gutter system. Here is a quick rundown of how to use one of these rainwater collection systems:

  1. Purchase a large rainwater collection barrel, tank, or food-grade plastic drum.
  2. Thoroughly clean out the inside of it.
  3. If your container does not have a spigot or bunghole, you will need to attach one. Due to the potential for collecting sediment and particles from your gutters, you’ll want the spigot to be placed halfway down the container and not at the bottom. You can help reduce the amount of debris accumulated in the container by installing a flush diverter.
  4. Place the container at the base of your downspout. Some commercially available rainwater collectors will have a downspout conversion kit, making the hookup easy. For more DIY methods, you’ll need to remove the bottom of your downspout and attach a downspout extender (a bendable plastic pipe.)
  5. Ensure the extender fits snuggly into the hole at the top of the container to keep out pests like mosquitoes, spiders, and bees. If you’re experiencing pest issues with these tanks, you may want to use a rubber seal or cover.
  6. If your container does not have an overflow hole, you’ll want to add one. To do so, drill a hole on the top of or along the side of the barrel.

Greywater Recycling

When properly drained from home appliances, greywater can be a great source of water for your plants. You have multiple options for obtaining, storing, and dispersing greywater. What options work best for you will come down to the time, money, and effort you want to put into your greywater recycling and distribution system. Cheaper approaches are quicker and easier to install but offer fewer options and capture less water. More expensive systems will draw from multiple sources and store, filter, and disperse it more effectively. But these take longer to install, require trained professionals, and often demand costly permits.

The easiest and cheapest method for recycling greywater is to buy a diverter and install it on the back of your washing machine. A diverter is a three-way switch that allows you to choose the destination of your washing machine’s greywater. With these handy fixtures, you can pump your greywater into the sewers or a container for later use.

Another option is to purchase a greywater recycling system. These divert, store, and pump greywater into containers or directly into irrigation pipes beneath your lawn and garden. These can be expensive and difficult to install, requiring a professional plumber and digging irrigation trenches in your yard. However, these systems simultaneously pull from your kitchen, bathrooms, and appliances. They also include handy features like filtration and overflow options, creating cleaner greywater and providing safer storage. Because of their efficiency and the money they can save on water bills, these systems can eventually pay for themselves.

Greywater Recycling Permits

While recycling greywater is efficient, the legality of it can be complicated. Many states and municipalities classify greywater as sewage, and it does not meet water quality standards for irrigation. Many states, therefore, outright ban household wastewater reuse or require special permits for recycling it. Before you install a greywater treatment system or purchase a diverter, you’ll want to ensure that it is legal in your state and seek out any necessary permits or permissions for installation.

Is it Safe to Use Greywater on Plants?

When using greywater, you’ll have to be mindful. While cleaner than blackwater, it still contains harmful chemicals or pathogens. Greywater is safe for lawns, decorative plants, trees, bushes, and foliage. Something to note is that you should avoid using harsh chemicals in your washing machine. Specifically, you should steer clear of soaps, detergents, and fabric softeners that contain sodium, borax, and bleach. These chemicals can damage your plants and contaminate your soil. You should also always alternate between using greywater and clean water on most plants, as this helps filter out and prevent the buildup of chemicals in your soil.

Can You Use Recycled Water in Vegetable Gardens?

You must take several precautions to use greywater in your vegetable garden safely. First, you should not use unfiltered greywater on any plant you consume. Many guides state doing so is completely safe, but unfiltered greywater carries a greater risk of dangerous diseases like E. coli. As such, you should avoid using unfiltered greywater on everything but decorative plants and your lawn.

You must also take caution when using greywater from the kitchen. Greywater from the kitchen sink and dishwasher is more hazardous than that taken from appliances, bathroom sinks, and showers. There is even debate going on right now about the classification of kitchen wastewater and whether it should be classified as blackwater, greywater, or a combination of the two (sometimes called dark greywater.) Because of this, we do not recommend using kitchen greywater to irrigate any crop or edible plant, especially if it’s unfiltered.

As for non-kitchen greywater, while it contains hazardous materials, you can still use it to water certain crops. To do so, you must ensure the greywater does not come into contact with the edible portions of any plant you water. If you use greywater to irrigate your garden, you’ll want to avoid using it on plants whose edible portions contact the ground, such as:

  • Root vegetables
  • All leafy greens
  • Squash
  • Melons
  • Cucumbers
  • Garlic
  • Onions
  • Radishes

You’ll have to take care when dispersing greywater and only do so on flat surfaces, so the water cannot stream or pool. Greywater should never be put through a sprinkler system, as the water can splash and contaminate the higher, edible portions of plants. Finally, you should never use greywater in gardens next to streams or swampy areas, as it can pollute local groundwater, surface water, or other water bodies like ponds or lakes.

What Are the Best Garden Plants To Use Greywater Water On?

With all the limitations of greywater, you might be asking what you can use it on. The answer, surprisingly, is quite a lot. You can use greywater to irrigate garden plants like:

  • Tall growing veggies, such as corn
  • Most berry bushes (with the exception of strawberries)
  • Fruit trees
  • Nut Trees
  • Tall vining fruits like grapes

Final Thoughts

Conserving water might feel like a daunting task. But you can cut back on your utility bills while keeping your garden alive and thriving by using reclaimed water. While recycling water requires precautions, patience, and a little know-how, it helps improve your home’s environmental sustainability.

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