Among RVers, few subjects get quite as much discussion as holding tank chemicals. Everyone, it seems, has their own favorite commercial brand, or on the other hand, their own “home brew” mixture to keep down offensive odors. Somewhat akin to religion or politics, more than one verbal sparring match has broken out around the campfire over what’s best. Now the State of California wades into the holding tank chemical controversy with a decision released at the turn of the year: no more formaldehyde.
In January, the California Department of Toxic Substances Control released a ruling that forbids the use and sale of any chemical toilet products containing formaldehyde. While not outright banning the use of other popular additives, the agency nevertheless released a strong advisory that RVers dump the use of certain other popular holding tank chemical additives.
Admittedly, not every RVer will ever set wheels in the Golden State, but it does raise a flag: What’s behind the ban and the advisory? What negative effects do these toilet chemical additives produce? And where does this leave RVers who have a conscientious concern about the “footprints” they leave behind, but at the same time still want to breathe fresh air—even in the vicinity of their holding tanks?
Treatment Ingredients
As far as California is concerned, formaldehyde “may be a non-biodegradable toxic chemical substance,” and hence, the outright ban of its sale and use there. In a study carried out by Washington State government, it was found that the most popular holding tank chemicals used by RVers contained formaldehyde, combined with methanol (alcohol). What’s the problem? While some manufacturers claim that formaldehyde is biodegradable (i.e. it breaks down or reduces to a strength that is harmless to the environment), the Department of Toxic Substances Control doesn’t necessarily agree. The real bottom line is this: While formaldehyde can kill nasty holding tank odors, at the same time it can also kill bacteria essential to the effective operation of septic tanks. Too much formaldehyde can bring the “digestion” process of a septic system to a complete halt, allowing the release of harmful bacteria into the environment.
Environmental concerns notwithstanding, formaldehyde (and methanol) are both poisons. Should a child (or anyone) somehow ingest a holding tank chemical containing these substances, the resulting harm is not something any of us would want to consider.
What about other holding tank chemicals? Are they any better? Let’s take a quick spin through the world of holding tank ingredients.
• Paraformaldehyde: Like formaldehyde, this substance is a microbiocide—meaning it kills bacteria. According to the U.S. Environmental Protection Agency, when heated, paraformaldehyde can release formaldehyde. It’s also highly toxic—just a teaspoon of this chemical can kill an adult.
• Bronopol: A “bacterial pesticide,” bronopol is also known as an antimicrobial. You’ve heard of those—they’re becoming very popular in hand soaps. Antimicrobials kill all sorts of bacteria—including helpful ones. Recently the United Nations World Health Organization cautioned that the widespread use of antimicrobials is leading to an alarming increase in the growth of bacteria that are resistant to drugs, leading to potential health catastrophes.
• Quaternary ammonium chloride: These also disinfect holding tank wastes. The Washington State study found that quaternary compounds are also responsible for killing off beneficial bacteria.
• Nitrates: A common ingredient in fertilizer, nitrates are extremely water soluble—they don’t bind with the soil. As a result, nitrates can percolate down through the soil and into the water supply. High levels of nitrates in drinking water create health risks in both children and adults.
• Detergents, dyes and perfumes: While intended to make holding tanks more ‘nose pleasing,” studies show that these additives can increase holding tank toxicity, adding to the threat of killing off beneficial bacteria.
• Enzymes: These additives tend to support the breakdown of sewage bacteria. This is a positive thing, as when holding tank wastes break down, the odor goes away.
• Bacteria: Bacteriological agents add the “right” kind of bacteria to the holding tank, boosting the breakdown of holding tank wastes. They should cause no harm to a septic system.
Home Brews Better?
Many RVers see themselves as stewards of the environment. A review of many common holding tank ingredients would tend to make us think twice before tossing them down the toilet. What about “home brew” chemistry? The Washington State study looked into what some RVers cooked up to hold down holding tank odors.
To quote the study, “Homemade mixtures of household cleaners containing disinfectants or cleaners to which disinfectants have been added should be discouraged. The amount of these mixtures used to control odor and the activity of microorganisms causing the objectionable odor are not known. Thus there is a tendency by the RV users to add an excessive amount of their ‘homemade’ preparation to the waste water holding tanks.” (Italics ours.) The result? The quantity of the home brew could be high enough to “shock” a septic treatment system, rendering it ineffective in treating sewage.
Evidently one of the most common “remedies” for holding tank odor is the use of pine oil, or pine oil containing disinfectants. The state survey rated it high on the list of substances toxic to septic system bacteria; hence the advice NOT to use do-it-yourself treatments.
Bottom Line
What’s an RVer to do? The State of California’s advice is, “Look for biodegradable (enzyme or citrus-based) products.” While nearly all holding tank chemical treatments claim to be “biodegradable,” the term itself can be nebulous at best. To truly be termed biodegradable, all ingredients must degrade into simple substances—carbon dioxide, water, and minerals in the environment.
From where we sit, it seems the safest holding tank treatments are those that are based on bacterial or enzyme (or both) ingredients, while avoiding those that might have added perfumes, dyes or detergents. We’ve used such treatments over the years and have been generally pleased with the results.
Nevertheless, if you do decide to make the switch to an enzyme or bacteriological based treatment, be sure to follow the label instructions to the letter. If you’ve used toxic substances in your holding tank in the past, you’ll need to thoroughly flush the tank following those label instructions, or you stand a good chance of “killing off” the good bacteria before it even has a chance to work.
As RVers, we appreciate nature and all its beauty. As stewards of the earth, let’s do all we can to ensure the footprints we leave behind are ones that cause as little harm as possible.
Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics. They also provide great resources in their book, Camp Hosting USA—Your Guide to State Park Volunteering. Visit www.icanrv.com for more information.
Nikki is a writer and editor for Do It Yourself RV, RV LIFE, and Camper Report. She is based on the Oregon Coast and has traveled all over the Pacific Northwest.
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