DIY Greywater System Build Instructions

*Build instructions courtesy of Climatebiz.com*

## How To Build A DIY Greywater System

A greywater system will decrease your carbon footprint, save water and decrease your utility bills. The system recycles water from your home and allows you to use it again for irrigation and flushing toilets.

It can be a simple, low-tech system that will be cost-effective in the long run and lower your water usage by up to 40%.

The best part? You can build it yourself!

The following article will outline what you’ll need to build your greywater system. This guide has it all, from understanding how a greywater system works, to breaking down the required materials!

### **How Does A Greywater System Work?**

#### What Is Greywater?

As previously mentioned, greywater is recycled water from your home. More specifically, water collected from showers, sinks, baths, etc. As long as the water hasn’t come in contact with feces or urine, it can be considered greywater.

#### How Does The System Work?

A greywater system aims to collect, filter and store greywater. Different systems achieve this in different ways. However, if we look at these systems, they can be divided into four sections:

* Pretreatment
* Filtration
* Storage
* Outlet/Irrigation

#### Pretreatment

To prevent your filter from clogging, it’s essential to pretreat the greywater by filtering out grease and other oils. The most efficient and low-cost way to do this is by using a **biofilter**.

A biofilter is a simple component made from organic material such as straw or mulch. Just grab some mulch from your compost heap or use leaves and grass cuttings from around your garden. Place your organic material into a container that will allow water to drain but keep the mulch in.

When the greywater flows into the filter, the organic material will absorb the grease and oils. The water will then drain into the next stage of the system, the filter.

#### Filtration

Your greywater needs to be filtered through a coarse filter to remove debris and most of the dirt. This type of filter is often made from sand and gravel.

The filter is made from three layers:

* Course Gravel (Distribution)
* River/Fine Sand (Filtration)
* Course Gravel (Drainage)

The greywater will flow over the first layer of gravel, leaving big pieces of debris behind. This later is on top of the filter and be cleaned as often as you’d like. Then the water will flow through the sand layer. The sharp edges of the sand grains catch the tiny debris and dirt. This layer filters the water and is the most vital part of the filtration process. The water then drips through the sand and into another layer of gravel. The second gravel layer allows the water to drain from the filter and into the storage tank.

#### Storage

Storing your greywater is the 2nd most flexible part of the system (just behind irrigation). The storage ultimately depends on how much greywater you plan on capturing. Another thing to keep in mind is how fast you’ll use the water. If you capture all the greywater in your home but only water your garden bi-weekly, you’ll need a large tank. If you’re only planning on capturing sink water, a small storage tank (like a large trash bin) will be suitable.

You’ll need to seal your storage tank to prevent smell and human contact. Greywater can contain pathogens, so the less contact you have with it, the safer. We also highly recommend an overflow device so that the system doesn’t start backing up.

#### Outlet/Irrigation

Now it’s time to decide how you’d like to use your greywater.

If you’re planning to use it to water your gardens, this is where you’ll connect your irrigation system.

If you’re planning on using it to flush your toilets, a more complicated pump system would be required. Alternatively, using a bucket system is a cost-effective way to flush your toilets or water your garden.

We recommend that the greywater doesn’t touch your fruit or vegetables directly. Instead, it should water the plants’ roots. Greywater is entirely safe to water all plants, but there are some suggested irrigation methods. For example, drip irrigation would be a great way to water your vegetables or even flooding. Adding a simple tap to the storage tank would allow you to fill buckets with water or drain unwanted water.

### Tools and Components Needed For DIY Greywater System

#### Tools Needed

1. **Cordless Drill** - A drill is something that most homes already have. If you don’t have one already, we suggest that you invest in a quality drill, ASAP.
2. **Hole Saw** - A hole saw is an attachment for a drill that allows you to drill large round holes. If you’re using storage tanks that don’t already have holes for the pipes to fit, too, you’ll need this.
3. **Screwdrivers** - You’ll need a set of screwdrivers to tighten the clamps and possibly other screws whilst building your system.
4. **Hacksaw** - You’ll need a hacksaw to cut the PVC pipes to the correct size.
5. **20 Litre Bucket** - You’ll use this 5-gallon bucket to create your DIY water filter.
6. **Netting** - As for the netting, you can either line the whole bucket or cover the outlet pipe. But, again, the purpose of the mesh/netting is to keep the organic material inside the bucket.
7. **Wood Chips** - When it comes to organic material, you can use straw, leaves, mulch, or wood chips. Essentially, any organic material that can absorb oils. You can find most of these materials around your garden, but you can also buy wood chips for the filter.
8. **Sand Filter** - The sand filter consists of 3 components: the container, gravel, and sand. You can use a 5-gallon bucket for the container, just like the one we used for the biofilter. However, a larger container will allow more sand and better filtration. You’ll need course gravel for two layers and sand for one layer. It’s best to source gravel and sand from your local building warehouse.
9. **Storage Tank** - The storage tank you’ll need will depend on how much water you’d like to store and your greywater usage. You could use a smaller tank that’s 200 Litres. This tank is for a minimal greywater system. A tank like this would be good if you’re only collecting sink water or maybe only shower water. You’ll also have to use the greywater quite quickly if you don’t want your tank to overflow. However, if you’re looking to have a more extensive system or plan to use the water slowly, you’ll need a larger tank. 400 Liters (100 gallons) is a decent size tank that will allow you to collect greywater from showers and sinks. The tank we’ve linked to has inlets and outlet valves, so some of the piping mentioned won’t be necessary.
10. **Piping** - You'll need a selection of 2 inch (50mm) pipe or wider, with straight pieces, elbows, T-joints, couplers, and PVC cement glue.

#### How Much Does It Cost To Build A DIY Greywater System?

It’s hard to say how much a greywater system will cost. Each system is different.

For example, a small system with no irrigation attached will be cheaper than an extensive system. Smaller tanks are more affordable than larger tanks. The distance from your shower to the greywater storage tank will influence the cost of piping needed.

Below, we’ve created a table that highlights each component of the system costs on its own. We’ve then estimated how much it might cost.

The cost for this greywater system is simple. However, it’s safe to assume that your system might cost more depending on how big it is. What’s more, the above system doesn’t include the cost of installing irrigation.

Next up we’ll look at a DIY greywater system that recycles your laundry greywater. This is one of the cheapest systems you can install.

### **How To Build a DIY Greywater System (Step-by-step)**

In this section, we’ll look at how to build a system that collects water from your washing machine. This is one of the cheapest and easiest systems to install as you won’t need to change much of the existing plumbing.

Bear in mind, each state has different codes and regulations for greywater. For example, some codes require a three-way valve when installing a greywater system to your shower. You can however easily divert the water from your washing machine into a greywater system.

#### STEP 1 – Plan Out The System

For your system to be effective, you’ll need to plan it out.

Where are you putting the storage tank? Where will the pipes connect? Will the greywater flow out over the garden, or will it feed into an irrigation system?

Our design has the greywater filtering into a storage tank. The tank will have a tap on it, which we can use to fill a bucket or connect a hose too. Then we’ll use the greywater to irrigate a vegetable garden via the flooding method.

#### STEP 2 – Start By Creating An Outlet For Your Washing Machine

Now that you’ve planned where everything goes, you’ll need to drill a hole through the wall. The piping will need to go through the wall to connect the washing machine to the system.

The pipes we are using are 2″ in diameter. Therefore, we’ll need to drill a hole slightly larger than the pipe for it to fit through the wall.

If you’d like your system to work on gravity, the filters will need to be placed lower than the washing machine outlet. The water would then flow through the filters and into the storage tank.

#### STEP 3 – Create The Biofilter

Next, you’ll need to position the bucket for the biofilter so that it can connect to the washing machine outlet.

Take a bucket (bucket A) and drill a hole through its side, near the bottom. Then insert one of the PVC pipes so that part of the pipe sticks into the bucket. Next, use Weld-On to seal the gap between the PVC pipe and the bucket. Repeat the process on the other bucket (bucket B) and set it aside.

Now we’ll cover the pipe inside of bucket A with fine netting. This will prevent the organic material from washing it. Next, secure the net to the pipe with wire or a zip tie. Finally, fill the bucket up with leaves, wood chips, or mulch.

#### STEP 4 – Create The Sand Filter

In bucket B, fill 1/3 of the bucket with gravel. This will act as the drainage layer. Next, fill another 1/3 with sand, which will serve as the filter. Finally, top the bucket up with more gravel, forming the distribution layer.

#### STEP 5 – Connect The Filters Together

You should align the filters so that gravity causes the water to flow through the system and into the sand filter.

The biofilter should be placed slightly higher than the sand filter. You can place the filters on supports or place them on shelves attached to the outside wall.

#### STEP 6 – Connect The System To The Storage Tank

The last step is to add a coupling to the pipe sticking from the sand filter. Then, fasten another PVC pipe that connects your storage tank to the other side of the coupling.

Make sure to seal all joints with Weld-On. This cement sealant will prevent any water leakages.

Leave the sealant for 24hrs, allowing it to cure. After that, your system is ready to use.

### Final Thoughts

Installing a greywater system may seem overwhelming but it can become a fun project. This DIY greywater system won’t only save water but also decrease your monthly water bill.

There are so many different systems out there, along with a wide range of home setups.

So while it can be a bit challenging to describe precisely how you should set up a greywater system and how much it would cost, this guide should go some way in helping you with the process.

## What's In Greywater?

You may have heard of greywater and how it can save you both water and money, but what exactly is in greywater?

Greywater is used water from your household. Household activities such as dishwashing, showering, bathing, and laundry use clean water and create greywater. Basically, all water except the wastewater from your toilet is greywater.

As we work towards a more sustainable future, we have become more innovative and aware of our resources. For example, recycling greywater is a growing concept, with more and more homes using a greywater system to recycle their water.

*What is in Greywater?*

Well, since it’s used water straight from your taps, we should look at what’s in the water supply.

Purification centers use various chemicals to process water before entering our water supply. These chemicals kill bacteria, algae, and other parasites. The chemicals also prevent foam from forming and allow their purification systems to operate efficiently, providing cleaner water.

Tap water contains the following chemicals:

* Chlorine
* hydrogen Chloride
* Natrium Hydroxide
* Copper & Iron
* Oils & Silica
* Nitrates
* Ammonia
* Flouride

These chemicals come in small amounts – they aren’t harmful to humans. However, since these chemicals are used to target/eliminate the growth of organic organisms, they could potentially be detrimental to natural environments.

When we look at greywater, we see all the above chemicals with whatever products we use in our homes. So, for example, greywater from the average household would contain washing detergents, surface cleaners, hair products, skin care products, and beauty products.

A study showed that **90% of greywater is soap**. Thus, when we plan on using greywater, we need to be careful of the detergents and cleaning products we use.

Many detergents change the pH level of the water or contain volatile organic compounds. These could make greywater harmful to your plants and the environment around you.

### Is Greywater Harmful To Humans?

When it comes to greywater and human safety, it’s not the greywater that is a concern. Instead, it’s the bacteria, viruses, and tiny organisms in it that can be harmful to us. Collectively, these are referred to as pathogens. These pathogens can come into contact with us when we wash our hands or clean cuts, potentially causing us to become ill. Therefore we must keep the greywater in a closed system and not handle the water. Washing your hands after working with greywater or a greywater system is also advised.

The World Health Organization (WHO) has released multiple studies and guides when dealing with greywater and using it in agriculture.

### Is Greywater Safe For Your Plants?

Whilst the pathogens in greywater may be harmful to humans it’s safe to use on your plants and gardens.

As long as you don’t use detergents that contain volatile compounds, almost all plants can drink greywater. However, how we water them is crucial. For example, decor plants can be watered with hoses and sprinklers, whereas grass can be watered with sub-surface irrigation.

### Greywater And It’s Affect On The Environment

Certain factors influence how the soil absorbs greywater and what it leaves behind. We need to understand two factors before we explore this further. These are – Biochemical Oxygen Demand and Chemical Oxygen Demand.

**Biochemical Oxygen Demand** (BOD5) - BOD5 is the amount of oxygen required for the bacteria and other micro-organisms to break down organic matter. Without a sufficient supply of oxygen, the organic mass in the greywater won’t decompose properly.

**Chemical Oxygen Demand** (COD) - COD measures how much oxygen needs to be present for there to be bacterial activity inside the greywater. Whilst BOD5 is a natural test, COD uses chemicals to determine the oxygen demand.

**The Relationship Between BOD5 And COD** - As studies explain, the ratio of BOD5 to COD determines how well the greywater will decompose. On average, the ratios range between 0.3 and 0.71. These figures indicate that just under half of greywater is entirely biodegradable.

When we use heavy cleaning detergents, it causes the ratio to change. When the COD is much higher than the BOD5, there is insufficient oxygen in the water for bacterial activity.

### Greywater And It’s Affect On Your Plants

Now that we understand how detergents change how greywater decomposes, we can look at how the greywater affects your plants. While too many chemicals can be harmful to your garden, certain chemicals help the plants in different ways. Chemicals that aid in the plant’s development are considered fertilizers. The 3 main chemicals that act as fertilizer are:

* Phospherous
* Nitrogen
* Potassium

All three help plants in different ways. For example, Phosphorous promotes root growth, while Nitrogen aids in food processing and chlorophyll development.

These three chemicals can be found in various cleaning products or through food waste. These chemicals also tend to end up down the drain and thus in greywater. So they fertilize our gardens without us even knowing.

 Nitrogen
 Potassium

There is also a flip side to this. While the chemicals mentioned above help provide the plants with nutrients, they can also change the soil’s pH level. For plants and crops to grow, the soil should maintain a pH level between 6.0 and 7.0. Acidic products like bleach or hand soap would bring the pH above this level. This alkalinity level would counteract the chemicals that fertilize the plant, harming them instead.

### Can I Use Greywater For My Vegetable Garden?

Yes, but don’t water your garden with sprinklers or a hose.

The best way to water your vegetable garden is through underground irrigation. The plant roots will process the water and ensure that the chemicals don’t affect the vegetables or fruit. Greywater is recommended for fruit trees as these trees often have a high water demand. In addition, because the water is recycled, you can water your plants guilt-free.

The only thing to watch out for is watering your vegetable garden with a hose. The last thing you want is the greywater to get onto your vegetables, carrying pathogens with them. If you’re interested in installing smart irrigation systems for your vegetable garden, we have an article that explains all you’ll need to know!

NPOs and governments use greywater to battle food scarcity in countries with severe water restrictions or drought. In addition, greywater is used for agriculture with no effect on the crops or produce.

### What Harmful Contaminants Are In Greywater?

As mentioned above, the main concern with greywater is pathogens. These can enter the greywater system through handwashing, wound cleaning, or bathwater. Pathogens can be dangerous to your health, causing ailments such as diarrhea, vomiting, stomach pains, and severe dehydration.

Other than pathogens that can affect our health, certain chemicals in household products can be harmful to the environment.

Here are a couple of chemicals in household products that are harmful and found in greywater:

 Octinoxate
 Parabens
 Triclosan
 Sulfates
 Microbeads

To avoid these chemicals contaminating your greywater, you should switch to cleaning products containing organic or natural ingredients. The same approach applies to skincare products and makeup.

Detergents that use natural chemicals tend to do less harm to the environment and decompose faster. Other detergents contain less acidic or basic chemicals, such as baking soda or vinegar. The only downside is that organic and natural detergents often cost more. However, many environmentally conscious people create their detergents from household products to get around this.

The bottom line – we should move away from heavy cleaning detergents or use them less. Regardless of whether you’re planning on installing a greywater system or not, taking this step has positive outcomes both ways.