6 Places That Sell RO/DI Water

Posted by Miles Harrison on 01/07/2023

Whether you need RO/DI water for a reef aquarium or some other purpose, it can be difficult to find places that sell it.

Luckily, there are a few options available. In this post, we’ll recommend 6 places that sell RO/DI water, and we’ll briefly discuss the pros and cons of making RO/DI water at home.

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What Is RO/DI Water

RO/DI stands for reverse osmosis/deionized water. It is water that has had most of its impurities removed through the process of reverse osmosis and deionization.

Reverse osmosis involves forcing water through a semipermeable membrane, which removes ions, molecules, and larger particles. Deionization is a process that removes ions from water by using ion exchange resins to attract and bind the ions.

RO/DI systems are often sold by their "stages", the more stages of filtration, the better a job the system does at filtering the water. Systems with more stages tend to be more expensive, but perform better and last for a longer period of time without needing to be replaced.

Image of an RO/DI system
Marco Verch Professional Photographer/Flickr
Image of an RO/DI unit

Where To Buy RO/DI Water

There are two choices when purchasing RO/DI Water, you can drive to a location that sells the water in person, or you can purchase the water online and pay for any extra shipping costs.

Both options have their pros and cons.

In Person

Purchasing RO/DI water in person is generally the most cost-effective route, but it does have its drawbacks.

Stores that sell RO/DI water are typically rare, and you often have to walk or drive long distances to find one. You’ll also need to carry large heavy jugs of water around, which for some might be a welcomed form of exercise.

Here are some of our favorite in person options for purchasing RO/DI water.

Local Fish Stores

It’s always worth phoning up your nearest local fish store to inquire if they sell RO/DI water. Many stores that specialize in saltwater aquariums often sell RO/DI water by the gallon. You’ll most likely need to bring your buckets to fill, but you can leave knowing that your purchase has supported a local business.

Unfortunately, local fish stores can be rare depending on where you live, but it’s worth googling fish stores near me to see if any stores have opened up in your neighborhood.


What doesn’t the Walton family sell? Walmart stores are massive, and they offer a ton of consumer products. While they no longer sell aquarium fish , some stores still sell RO/DI water by the gallon.

It doesn’t hurt to phone up your local Walmart’s customer support team and inquire about whether or not they sell RO/DI water. For the stores that do, prices tend to average around $1/gallon.

You can find your nearest Walmart's customer service number, by using their store locator tool .


It isn’t just home improvement products that Lowes sells - some of their large stores sell RO/DI water by the gallon.

You’ll want to phone up your local Lowes and ask, but it can be difficult to find the right number to call. Luckily we know the trick, do a quick google for lowes near me , and jot down the store location. Then head over to their store directory page. You should be able to find your closest store's Main phone number. (Avoid calling the Pro Desk, that number is for general contractors!)


Purchasing online has its drawbacks. It can be more expensive due to the added shipping costs, and it’s also susceptible to delays in shipping, which can become a problem if you need your RO/DI water ASAP.

However, you can’t beat the convenience of online shopping, and if there’s no local alternative, it might be your only option. Plus let’s face it, your time is valuable. If the closest store is an hour away, that’s at least 2 hours in travel time just to purchase a version of something that comes out of your faucet for free!

Here are some of our favorite options for online purchases.

Image of an RO/DI system
Kingfish101/Wikimedia Commons
Image of an RO/DI electric system


ChemWorld is a chemical supplier and a stocking equipment distributor with locations in Michigan, Utah, and Georgia.

Luckily, these folks offer RO/DI water , and you can order two 1-gallon jugs for about $70. They do have sales, and we’ve seen their prices drop as low as $33 with free shipping included.

Seatech Aquariums (Phoenix, AZ only)

If you live in Phoenix Arizona, you may already be familiar with Seatech Aquariums. Owner Jimmie Hernandez has over 20 years in the aquatic industry, and his business offers water delivery services.

His prices are extremely reasonable , charging only about $.65/gallon. If you’re in the Phoenix area this is an exceptional deal.

Light Fish

Alright, so if you don’t know already, Light Fish is a marketplace for those in the aquarium hobby, which means we see all sorts of aquarium-related products go up for sale.

It’s worth taking a look at our filters and current section to see if any RO/DI water jugs are available, you may snag a great deal!

DIY (Do It Yourself)

If you’re the type that likes to plan for the future, then you might want to invest in an RO/DI system. These units pay for themselves in the long run, and they’re easy to set up and use.

Unfortunately, these units have their drawbacks. They are often quite bulky and take up a lot of space, and you’ll need to wait a long time for the water to properly filter. It can take quite a few hours to make a few gallons of RO/DI water depending on the filter you choose.

Not everyone has the patience or time to create their own RO/DI water at home, but if you can afford a reliable unit and have the space, you’ll have the ability to make RO/DI water at a moment's notice.


As you can see, you have quite a few options for purchasing RO/DI water. You can purchase gallon jugs online, in person at your local fish or hardware store, or you can create RO/DI water yourself at home.

There are pros and cons to each method, so which do you think will be best for you? Let us know by commenting below, and be sure to check out our community forum where other hobbyists discuss everything related to fish keeping.

Image of Miles Harrison

Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!