Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle. If you take offense at this, please do not continue reading except to be helpful in the scientific goal. I know this subject won't suit many types of people, so just ignore it if that is your case.

I noticed first of all that urine is not at all as sterile as people say that it is. The rate of growth of bacteria is relatively slow, but as a precaution, I found the need to use additional measures to prevent the growth of bacteria. I settled on the following method: I have two bottles and I add to each bottle about enough salt as can be soluble in the urine and sometimes maybe a little more. The one bottle then fills up throughout the day and is emptied, washed, and refilled with salt. The salt helps to kill the bacteria which would be lingering in the empty bottle. The next day, the bottle stays empty and the other is used.

I would add that I discovered that the bacteria (without the salt) does not usually grow unless the bottle is left with urine for two days. After this, however, that same bottle (without the salt) would retain the bacteria and immediately grow, if used again.

This system works relatively well, so long as it is done every day. It will even withstand 2 days with only moderate growth. (If I should leave it by mistake for longer it can get ugly). Nevertheless, I am still looking to improve upon this. One reason is that, if I drink less water or relieve myself normally, the bottle does not fill in one day. I am looking for someone with knowledge of chemistry to help me find a substance that can be added to this solution which fits a number of common sense criteria. I will also add a list of the substances that I have tried or already considered.

Necessary qualities

  1. Safe to be handled and mistakenly touched. Implied that it will not eat through the plastic bottle. I can obtain a suitable glass bottle only with difficulty.
  2. Something that will not kill a dog or a human through trace amounts, should they drink from the (clean) toilet bowl. For example we put ammonia in toilets, flush it, no problem.
  3. Very important - something that will not react with the urine to produce gas, thereby causing the bottle to explode or expand. Something that will not (implied) produce a distinctively offensive smell. An example of this would be chlorine.
  4. (Obvious) That it will be suitable to flush down the toilet.
  5. Something that is not too expensive, physically large, or heavy in the quantity that I intend to use it. An example of this would be diluted vinegar.
  6. Something not involving much preparation, easy to obtain, etc.

Substances considered

  • Vinegar: A moderate amount of vinegar did not have any effect. More than this would be difficult to obtain and store. Even at 5x the strength, I think it would still require a large amount, and this is not sold in stores that I visit.
  • Chlorine/Bleach: I understand that this substance reacts with (things in) the urine and produces gas. It would produce a distinctive pool odor and I believe it can also cause burns.
  • Ammonia: Same issues as chlorine - it would produce an offensive gas that burns my eyes.
  • Acetic acid: similar to vinegar, except dangerous to handle. I don't even know that it would work.
  • L-ascorbic acid (Vitamin C): probably dangerous to handle in a concentrated form and I don't know that it would work. Basically the same as vinegar. I know that it is used as a preservative, so it came on this list.
  • Alcohol - might work, smell might be tolerable. I would need to know more about what concentration and amount to buy/use.
  • Hydrochloric Acid - no

There is a list of preservatives on Wikipedia, and one that just now caught my eye was Sodium Propionate ($20/lb on eBay). Might not be a bad idea; maybe someone knows about it. I would much prefer something that could be bought in a store. Since this urine won't ever be consumed by humans, we should have more options than common preservatives - maybe I/we could push the PH range out to one extreme to inhibit all growth. Someone more knowledgeable could tell me how/if that could work without becoming dangerous.

Ideally, I think would be something that stops the bacteria growth completely. Next best would be something that gives me an extra day or two if I need it.

Thanks in advance.


6 Answers 6



In this answer I will present to you several ways of optimizing your method, quickly summarized:

  • UV irradiation
  • Better Sanitization of the Bottles

Wait, shouldn't urine be sterile?

I noticed first of all that urine is not at all as sterile as people say that it is.

It has long been a myth that urine is sterile, but it was debunked this year in a study. There are in fact low amounts of bacteria present in urine. That being said, a high bacterial load in urine is an indication of an infection in the urinary tract and should not be left unchecked.

How do we know what is growing in there?

I don't know how you checked what kinds of microorganisms are developing in the bottled urine, it might also be more fungal instead of bacterial. This might also affect the way to counter the problem, so without knowing exactly what is growing in there, the solutions might be worthless. For now I consider bacteria as the sole contamination.

Now, let us proceed to the interesting part.

UV Irradiation

Let's start off fancy. If you continue with your workflow of intermediate urine storage in bottles, it might be worth looking into solutions involving UV irradiation as a way to reduce the amount of microorganisms in the bottle. Something as simple as a UV diode screwed into the cap might make a huge difference. Maintenance will be low, but the higher initial cost could put you off.

It is always worth considering long-term solutions.

Reduce Contamination of Bottle

I don't know how you prepare the bottles prior to peeing in them, but you might well reduce the problem by simply sanitizing the bottle properly. One way would be to boil the bottle in hot water for about 30 minutes. However, this is quite time consuming and thus defeating the purpose of the exercise.

Another method would be to rinse it well with (warm) water and diluted ammonia (which you then can flush down the toilet) and then swirling some sanitizing solution (think of the commonly available hand sanitizers) around the bottle, even leaving that in there. An advantage of this method is that hand sanitizers usually contain fungicides and viricides, so you kill several birds with one stone.

I don't know if that already is sufficient to guarantee a two-day period where bacterial growth is inhibited enough that you will not observe it, but it might be well worth checking out, as hand sanitizers are widely available and should keep the cost of maintenance low.


Sodium Propionate or Sodium Sorbate are both suitable for inhibiting bacteria growth and would not pose any problem (unless consumed in large quantities). The metal ion (calcium, potassium, sodium) associated with the organic acid is not very important. I'm not sure how much you would need to use, but a teaspoon should be sufficient. If you search for "food grade ...", you will be able to shop from your browser.

  • $\begingroup$ I'll go with that. Your link is actually calcium propionate (doesn't matter). I'll leave the answer unmarked for now in case others posts come along. Also, I noticed that Sodium Sorbate has PH requirements, but Calcium Propionate did not. $\endgroup$ Nov 10, 2014 at 5:33
  • $\begingroup$ @user1122069 I know, I did a search for food grade propionate and that was one of the cheapest. I don't remember the pH range for urine, but it should be between 5 and 8. Adding sodium sorbate will make the solution more basic. $\endgroup$
    – LDC3
    Nov 10, 2014 at 5:37
  • $\begingroup$ I may check out some boric acid also. I've been a day and a half with the calcium propionate and it looks like nothing has grown. $\endgroup$ Nov 14, 2014 at 19:02

I use potassium metabisulfite, sodium sorbate, or sodium benzoate as preservatives in winemaking. I have to think it would work here as well. All three should be readily available from a homebrewing or winemaking shop, and they are fairly cheap. They can also be purchased online fairly easily.

Amazon sells sodium benzoate for $14.00 per pound, which should be month's worth of preservative.


I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle.

So instead of walking into the bathroom... you just pee into the Poland Springs water bottle next to you? And then you decide to leave it next to you the next few days?!?!

All jokes aside, it depends on what you want to do with the sample. If it is strictly storage and you want to disinfect and neutralize bacteria while keeping odors at a minimum, probably the easiest and most efficient method would be either to raise or decrease the pH to sufficient levels such that bacteria growth is inhibited.

Urine contains a lot of compounds that are excreted from the body. Protens, sugars, nitrites, ketones, bilirubin, urobilinogen, erythrocytes, leuckocytes, etc, etc. (1)

Obviously, a concern that is immediately raised is disposal of such acidic or basic solution. Since you are working at home, you will generally not have designated or specific areas for such waste disposal. The easiest method is to dilute the urine solution with water sufficently such that the solution is effectively neutralized and is ~7.0 pH. You can check the pH of the solution by using Litmus paper or just standard pH paper which is relatively cheap to come by. Once you reach the desired pH limit, you can then pour the solution after "walking the moderate distance to the bathroom" and dispose of it in the toilet or sink, whatever floats your boat.

If you don't want to do that and instead want to hang on to the urine/acidic/or/basic/solution, you can order a carboy. (2) Needless to say, it can be quite difficult to pour into the carboy depending on the original container you have. Then you can send it off to your local hazardous chemical disposal facility. Yay. They might wonder why your carboy's are all filled with copious amounts of urine. Be prepared to answer honestly so they can in fact, properly dispose of such material since it is biological in nature.

Collection of Urine

Urine is prone to collecting bacteria and other cellular contamination. Yes, the urine that comes out of your bladder is sterile. Your urethra, I don't know about you, may in fact not sterile. Common procedures are to stick a sterile catheter first up in through your urethra and clean it, although, that is in fact highly unpleasant, and is very painful. The most easiset way to collect a more or less "clean" sample midstream clean catch specimen. First pee into one container for a few seconds. Hold and clench, and then pee into the container where you wish to collect your urine. Then hold and clench again, pee the remainder back in the first container. Ok, I'm wondering what you do about washing your hands...


Your container, must, must, must, must, be sterile. Every time you collect, you must use a new container. Can I say that again? It must be sterile. Otherwise it would defeat the purpose... so yea. The next question is, how long do you wish to store your urine next to you?

The most common containers are urine collection containers. These are generally the cups you pee in when you have a physical at your doctors. These samples are usually analyzed within the first few hours of collection.

If you wish to store for a longer period of time, say 24 hrs, a urine collection container is more suitable. This is a 3L container and is amber. The amber color is necessary since analytes such as porphyrins and urobilinogen are photosensitive.


Common 24-hour preservatives are hydrochloric acid, boric acid, acetic acid and toluene.(3) A lot of the literature is pointing towards boric acid as the preservative. UCSF medical center has a nice protocol which you can follow here. (4)

Boric acid is pretty cool since it's powdery and not so soluble in room temperature as other acids. Yea, get the tablet's since they are way easier to deal with than the powdered form.

Other methods include preservation at $4^\circ$C for first 24-hr. Then deep freeze at $-80^\circ$C for longer term storage. Those refrigerator's cost tens-of-thousands so yea... dry ice might work.


Commercial multi-surface cleaners are available in spray bottles that claim to kill "99.9 %" of bacteria. A squirt or two (or 3 or more) could do the job, especially when the urine is fresh and there are only one or two (million?) bacteria present.

The cleaners containing quaternary ammonium salts at less than 1% and seem to be safe, even if ingested in tiny amounts. These are to be distinguished from the ordinary toilet bowl cleaners, which often contain HCl to dissolve lime deposits.


I asssume the problem with the bacteria is that there is a problem with odor. Since you are going to flush away the urine anyway the problem must not be the bacteria itself but what the bacteria is causing. The odor problem is solved simply by not putting a lid on the bottle, and covering it with cloth instead. Leave it open to the air and there will be no noticeable odor. It will not be necessary to add salt. Urine already has salts in it. They will be deposited in the bottle. They can be washed out with very hot water from time to time.


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