Featured Deionized Water Products
Available in gallon and 32 oz sizes. All products meet ASTM D1193 specifications.
Your trusted deionized water supplier. Order ASTM-certified Type 1 Ultrapure and Type 2 Pure DI water with Certificate of Analysis. Fast nationwide shipping, bulk discounts, and subscription savings for repeat orders.
We're not a generic water supplier. Every bottle is produced to exacting ASTM standards with full traceability.
Every batch is tested against ASTM D1193 specifications. Type 1 achieves 18.2 MΩ·cm resistivity — the gold standard.
No guessing. Your Certificate of Analysis documents resistivity, TOC, conductivity, and bacteria counts for your exact batch.
Ships from Maryland via UPS and USPS. 1-2 day delivery in the Mid-Atlantic region. Competitive rates coast to coast.
Lab-grade deionized water at competitive prices. Save more with our four-packs and subscription options.
Deionized water — also known as DI water, demineralized water, or demin water — is water that has been purified through an ion-exchange process to remove virtually all dissolved mineral salts. This includes positively charged ions (cations) like sodium, calcium, magnesium, and iron, as well as negatively charged ions (anions) such as chloride, sulfate, and bicarbonate.
The deionization process works by passing water through specially manufactured resins. Cation resins exchange hydrogen ions (H+) for dissolved mineral cations, while anion resins exchange hydroxyl ions (OH−) for dissolved anions. The released H+ and OH− ions combine to form pure water (H₂O). In mixed-bed deionization, both resin types are combined in a single column to achieve the highest purity levels — up to 18.2 MΩ·cm resistivity, which represents theoretically pure water.
Why resistivity matters: Pure water resists electrical current because it lacks the dissolved ions that carry charge. The higher the resistivity, the fewer ions remain. ASTM Type 1 water at 18.2 MΩ·cm is as close to ion-free as commercially achievable — making it essential for sensitive analytical instruments like HPLC, GC-MS, and ICP systems where even trace minerals can interfere with results.
Unlike distilled water, which relies on evaporation and condensation (and may still contain volatile organic compounds), deionization specifically targets ionic contaminants with greater efficiency and throughput. When combined with additional purification steps like reverse osmosis, UV oxidation, and sub-micron filtration, the result is ultrapure water meeting the strictest ASTM D1193 specifications.
For everyday consumers, deionized water offers practical benefits too. Aquarium hobbyists use DI water to create a mineral-free baseline for precise water chemistry control. Auto detailers rely on it for spot-free final rinses. CPAP users prevent mineral scale in their humidifier chambers. And battery technicians top off lead-acid cells without introducing contaminants that shorten battery life.
Available in gallon and 32 oz sizes. All products meet ASTM D1193 specifications.
Deionized water isn't just for labs. Millions of people use DI water every day for hobbies, health, and home.
HPLC, PCR, mass spectrometry, reagent prep, and calibration. The standard in analytical chemistry.
Start with pure water and add only what your fish need. Essential for reef tanks and sensitive species.
Spot-free rinses for paint, glass, and chrome. No mineral deposits or water marks. Professional results at home.
Prevent mineral buildup in humidifier chambers. Extends machine life and keeps your airway clean.
Top off lead-acid batteries without introducing contaminants. Used in cooling systems and electronics manufacturing.
Start with a clean slate for precise nutrient mixing. No unknown minerals interfering with your grow formula.
Real feedback from labs, hobbyists, and businesses that rely on our deionized water.
We switched to ASTM Water Solutions for our HPLC-grade water and the consistency has been excellent. The COA with every order gives us the documentation we need for audit compliance. Our lab hasn't looked back.
I run a reef tank and water quality is everything. The Type 2 DI water from ASTM gives me a clean baseline every time. No more surprises with TDS readings. Shipping to Maryland is lightning fast too.
We detail 30+ vehicles a week and the spot-free rinse with DI water is a game-changer. Clients notice the difference immediately. The gallon jugs are easy to work with and the pricing is fair for the quality.
Both are deionized water. The difference is the level of purity.
Everything you need to know before buying DI water online.
Deionized water (DI water) is water that has had virtually all of its mineral ions removed through a process called ion exchange. This includes cations like sodium, calcium, and magnesium, and anions like chloride and sulfate. The result is extremely pure water suitable for laboratory, industrial, and consumer applications where mineral contamination must be avoided.
Deionized water is used in laboratories for reagent preparation and instrument calibration, in aquariums and reef tanks to create mineral-free water, in CPAP humidifier chambers to prevent mineral buildup, in auto detailing for spot-free rinses, in lead-acid batteries to avoid contamination, and in hydroponics for precise nutrient mixing.
Distilled water is purified by boiling and condensing steam, which removes minerals and many contaminants. Deionized water is purified through ion-exchange resins that specifically target mineral ions. DI water can achieve higher purity levels (up to 18.2 MΩ·cm resistivity) and is produced more efficiently than distillation. For most applications, ASTM-grade deionized water meets or exceeds distilled water purity.
Deionized water is not toxic and is safe in small amounts, but it is not intended as drinking water. Because it lacks minerals, it has a flat taste and does not provide the electrolytes found in regular drinking water. DI water is designed for laboratory, industrial, and specialty applications where mineral-free water is required.
ASTM D1193 is the standard that classifies reagent water into purity grades. Type 1 (Ultrapure) has the highest purity at 18.2 MΩ·cm resistivity with less than 10 ppb TOC — used for critical analytical work like HPLC and PCR. Type 2 (Pure) has greater than 1.0 MΩ·cm resistivity with less than 50 ppb TOC — ideal for general lab use, aquariums, batteries, CPAP machines, and auto detailing.
Yes. ASTM Water Solutions ships deionized water nationwide via UPS and USPS from Baltimore, Maryland. Customers in Maryland and the Mid-Atlantic region typically receive orders within 1-2 business days. All orders include a Certificate of Analysis documenting the purity of your specific batch.
ASTM Water Solutions is a Maryland-based supplier of certified ASTM D1193 deionized water and specialty chemicals. Every batch is produced to strict purity standards and ships with a Certificate of Analysis documenting resistivity, TOC, conductivity, and bacteria counts. We serve laboratories, research institutions, aquarium hobbyists, auto detailers, and industrial customers nationwide.
Certified ASTM deionized water, shipped to your door with a Certificate of Analysis. Browse our full catalog of Type 1, Type 2, and specialty products.
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