Will baking soda and vinegar unclog a drain?

Not reliably. Baking soda and vinegar react with each other, one to one, to make sodium acetate, water and carbon dioxide, so the foam you see is the two ingredients using each other up, leaving a weak salt solution in the pipe. NMSU and Georgia both publish a baking soda and vinegar drain method, but the Georgia card describes it as weekly upkeep "for slow drains," and NMSU lists a plunger or plumber's snake in the same breath. For a real clog, start with the plunger, then the snake, then hot water. This page gives that order, prints the published fizz methods for what they are, and explains why homemade lye or acid drain openers are a bad idea.

Work through a clog in this order

1. Plunger. NMSU names it first among its tools: "Use a plunger or plumber's snake" [1]. Use a cup plunger on sinks and tubs, cover any overflow opening with a wet cloth so the pressure goes down the drain, and plunge with water in the basin.
2. Plumber's snake (drain auger). NMSU's other tool [1]. A hand snake reaches hair and soap clogs in a tub or bathroom sink trap that a plunger cannot shift. Pull the clog out rather than pushing it further.
3. Clean the stopper. Hair and soap collect around a pop-up stopper in a bathroom sink. Lift it out and clean it by hand.
4. Hot water to flush. NMSU finishes its method with "Pour hot water down the drain" [1]. See the note on boiling water below.
5. Call a plumber if the drain is still blocked, if several drains are slow at once, or if water backs up into another fixture. Those point to a problem farther down the line than household tools can reach.

The published fizz methods, and what the fizz does

NMSU, Drain Cleaners (G-313, revised February 2019) [1]:

Use baking soda and vinegar: - Pour 1/2 cup baking soda followed by 1/2 cup vinegar into the drain. - Wait 10 minutes. - Pour hot water down the drain. - Use a plunger or plumber's snake.

University of Georgia, Drain Cleaner (HACE-E-73-1, revised October 2018), also on the Kentucky and Missouri cards [2][3][4]:

For slow drains, use this drain cleaner once a week to keep drains fresh and clog-free. - ½ cup baking soda - 1 cup white vinegar - 1 gallon (16 cups) boiling water Pour baking soda down drain/disposal, followed by vinegar. Allow the mixture to foam for several minutes before flushing the drain with boiling water.

Kentucky's card prints the water line as "1 gallon boiling water," without the cup conversion [3].

The chemistry is simple. Sodium bicarbonate and acetic acid react in a one-to-one ratio "to yield one mole of sodium acetate, one mole of water, and one mole of carbon dioxide" [5]. The carbon dioxide is the foam. Once it has finished, what is left in the pipe is a dilute salt solution. Both methods end with a hot water flush, and neither source reports a test of its method on a clog, so there is no published evidence that the fizz itself clears one.

That is why this page treats the fizz as optional upkeep for a slow drain and leads with mechanical tools for a blocked one. Combinations that cancel explains the same reaction in other recipes.

Boiling water and your pipes

The two sources differ: Georgia calls for "1 gallon (16 cups) boiling water" [2], and NMSU for "hot water" [1]. Neither says anything about pipe material, and no pipe or fixture manufacturer guidance on boiling water was found for this page. If you do not know what your drain pipes are made of, the cautious choice is hot tap water, as NMSU calls for, rather than a full kettle at a rolling boil. If you want a firm answer for your plumbing, ask a plumber who has seen it.

Why homemade lye or acid drain openers are dangerous

Commercial drain openers that clear clogs chemically carry serious hazards. NMSU lists what they can do: "Burns of the mouth and throat," "Throat swelling," "Organ damage" and "Possible death" if swallowed, "Irritation" and "Burning" on skin, and "Loss of vision" from eye contact, and says "Seek immediate medical help if drain cleaners are swallowed or there is skin contact" [1]. Federal packaging law requires child-resistant packaging for household products with free sodium or potassium hydroxide at 2 percent or more in a liquid or 10 percent or more in a dry product, and for those with 10 percent or more sulfuric acid [6]; the child-resistant closures page has the full list.

Mixing your own opener from lye or a strong acid means handling the same corrosive chemicals NMSU describes, without the tested formula, label directions or child-resistant closure a commercial product must carry. Do not make one, and never pour one kind of drain opener on top of another, or on top of bleach.

If you choose a commercial drain opener:

• Use one product only, by its label, with gloves and eye protection, and never follow it with another product. Using two cleaners one after another explains why.
• Do not plunge or snake a drain that has a chemical opener in it unless the label says that is safe, because the plunger can splash it back at you.
• Tell a plumber what you poured before they start work.
• If any gets in an eye, on skin or is swallowed, call Poison Control at 1-800-222-1222 [1] and follow cleaner in the eyes, on skin or swallowed.

Garbage disposals

Georgia's card set includes a disposal method that uses no chemical at all [2]:

GARBAGE DISPOSAL CLEANER - 1 cup ice - used lemon or orange rind To eliminate garbage disposal odors and clean and sharpen blades, grind ice and rinds until pulverized.

It is an odor and debris method; Georgia makes no claim that it clears a clog. Follow the disposal maker's manual for jams.

When a drain is fine but the sprayer is clogged

If the clog is in your spray bottle rather than your sink, the cause is usually the recipe. When a homemade cleaner streaks, clogs or leaves film covers washing soda crystals, settled cornstarch and how to clear a trigger.

References

1. New Mexico State University Cooperative Extension Service (revised by Rick Griffiths and Sonja Koukel), *Green Alternatives to Toxic Household Products and Hazardous Waste*, G-313, revised February 2019. https://pubs.nmsu.edu/_g/G313/index.html
2. University of Georgia Cooperative Extension (Pamela R. Turner and Sharon M. S. Gibson), *Green Cleaning: Recipes for a Healthy Home*, HACE-E-73-1 (Green Clean Booklet), revised October 2018. https://site.extension.uga.edu/greenway/files/2024/09/10.18_Green-Clean-Booklet_update.pdf
3. University of Kentucky Cooperative Extension (Connee Wheeler, adapted from Gibson and Turner, UGA), *Green Cleaning: Recipes for a Healthy Home*, HHF-CRW.175, January 2010. https://fcs.mgcafe.uky.edu/sites/fcs.mgcafe.uky.edu/files/green-cleaning-recipe-cards.pdf
4. University of Missouri Extension (Pamela R. Turner and Sharon M. S. Gibson, adapted by Kandace Fisher-McLean), *Green Cleaning: Recipes for a Healthy Home*, GH201, 2019 (GH-0201-2019 in the MU MOspace record), adaptation of the 2015 UGA edition. https://extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/pdf/hesguide/foodnut/gh201.pdf
5. Science Notes (Anne Helmenstine), *Chemical Equation for Baking Soda and Vinegar Reaction*, updated August 26, 2023. https://sciencenotes.org/chemical-equation-for-baking-soda-and-vinegar-reaction/
6. 16 CFR 1700.14, Substances requiring special packaging, via Cornell Legal Information Institute, read October 2026. https://www.law.cornell.edu/cfr/text/16/1700.14