What to Do With Urine From Compost Toilet

What to Do With Urine From Compost Toilet?

Table of Contents
Table of Contents

Unsure of what to do with the urine from the compost toilet? You’re in the right place. 

Whether it’s through dumping stations, soak-away pits, or fertilizer additives, this article discusses how to effectively and safely dispose of urine. 

We’ll also explain the advantages of separating urine from waste, as well as the primary components of urine that make it a suitable alternative to commercial fertilizers. 

out house toilet

Why Do You Need to Keep Urine Separate From Waste?

Separating urine from human waste allows feces to dry, effectively killing off harmful pathogens. 

Urine encourages bacterial growth in waste, turning it unsafe, unsanitary, and smelly. This is why regular sewage stinks and most composting toilets don’t. 

Sanitation advantages aside, the collected urine can also be used as fertilizer.  

Urine is rich in phosphorus, potassium, and nitrogen—three of the most crucial components of plant growth. 

Plus, it’s more or less sterile when it leaves the body. Unlike waste, which can carry harmful bacteria like E.coli and salmonella, urine poses little to no health risks when handled. 

According to data collected in the 2021 study published in the Agronomy for Sustainable Development, urine fertilizer produces a 30% higher yield than traditional fertilizers. 

Another study shows that beetroots fertilized with urine and urine-ash fertilizer (urine supplemented with wood ash) appeared 10 and 27% larger by mass than those grown in mineral fertilizers, respectively. 

A urine-diverting compost toilet allows you to capture excess urine into a urine container which can be used to collect it over time for use as a fertilizer.

What Is Urine? 

Urine is the liquid by-product produced by the kidneys through the ureters to the urinary bladder. It consists of 95% water, 2% urea, 0.1% creatine, and 0.03% uric acid and minerals, such as: 

  • Chloride 
  • Sulphate 
  • Sodium 
  • Ammonium
  • Potassium
  • Phosphorus
  • Other trace components like hormones, proteins, and metabolites

The kidneys release urine by filtering waste (called urea) and extra water from your blood. Urine travels down the ureters and to the bladder, where it stays until you’re ready to urinate. 

outhouse toiletThe bladder swells to a round shape when full and returns to its normal size when empty. A healthy bladder can hold up to 16 ounces (2 cups) of urine for two to five hours without issues. 

By using urine as fertilizer, you’re cycling back the nutrients from the food you consume while also diverting it from the water system, where it acts as a pollutant. 

Urine contains a significant amount of potassium, nitrogen, and phosphorus—three of the primary ingredients of fertilizers. It contains around 11 parts nitrogen to 2.5 parts potassium to 1 part phosphorus. Studies show that these nutrients are enough to fertilize 50 to 100% of the crops needed to feed an adult. 

Different Ways to Dispose of Urine From Composting Toilet 

Composting toilets separate urine from waste with the help of a urine separator. The separator diverts solid and liquid waste into two compartments, allowing you to dispose of the gathered by-products separately. Here are different ways to dispose of urine from a composting toilet: 

Use as Liquid Fertilizer 

cartridge composting toiletRather than buying imported nutrients for gardening, why not export nutrients from an organic material via the toilet? 

The chemical makeup of liquid fertilizers is much like the natural makeup of urine. 

Fertilizers—mineral or otherwise—are mostly made up of nitrogen, potassium, and phosphorus. Conveniently, all three can be found in urine. Therefore, you can make a plant feed solution with the urine you’ve collected from the composting toilet. 

To do this, dilute one part urine to 10 to 15 parts water for ground plants and 30 to 50 parts water for potted plants. Plants that require high amounts of nitrogen—tomatoes, corn, capsicum, cucumbers, squash, etc.—benefit from urine fertilizers the most.

Use as Compost Additive 

Urine speeds up the composting process, making it an ideal additive for compost. 

In a sense, it’s comparable to adding a commercial compost accelerator to boost the decaying process. Some even argue that the natural method is better (and, of course, cheaper) than the commercial product. 

It’s important to note that urine shouldn’t be stored for a long-time. Long-term storage not only increases the risk of bacterial contamination but also converts nitrogen to ammonia. Collected urine shouldn’t be stored longer than 24 hours before being used in your compost or garden. 

The ratio to be used for compost acceleration is 10 parts water to 1 part urine. 

Empty In a Soak-Away Pit 

A soak-away pit, also known as a soak pit or leach pit, is a porous-walled chamber that stores and soaks wastewater into the ground.  

Since discharge quantities for urine are minimal—around 1.5 to 2.5 liters per person—the soak-away pit doesn’t need to be large. A typical soak-away pit for four occupants is roughly 20 x 20 x 20 inches. The pit should only be used for urine and not shared with other wastewater outputs (like basins and sinks). 

To make a soak-away pit, simply dig a hole in the ground, fill it with hardcore and gravel, and either dump or run the urine pipe into the top of the pit. 

off grid toilet


When it comes to building an off-grid property, having a waste management system is an important step to becoming self-sustainable and maintaining proper hygiene. A lack of proper hygiene can attract unwanted pests, spread disease, or create foul and toxic fumes on your property.

As we have discussed, there are multiple ways to dispose of urine from a composting toilet. You can use it as fertilizer or compost accelerator or dump it into a soak-away pit. You can also empty the collected urine in a nearby RV dump station if it’s convenient. 

Urine is a carbon-rich material that can speed up the decomposition process and serve as a fertilizer for house plants and crops.

If you don’t have any of these options, empty out the urine on organic matter like soil or a patch of weeds instead of desirable plants. Be thoughtful and respectful to others and the environment. 

cartridge composting toiletIf you are looking for a urine-diverting toilet, know there are many varieties of composting toilets available to help with separating urine from waste. Each variety of composting toilets has its own pros and cons, so it is important to pick the one that works best for a unique living situation. We have narrowed down the list to our 6 Favorite Off-Grid Toilets to help you pick the one that is best for you. But for some people, they may prefer to make their own composting toilet at home.

If you want to learn more about maintaining an off-grid toilet, consider reading our post on 18 frequently asked questions about composting toilets.

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