Whether you're buying distilled water for a CPAP machine, an iron, or a humidifier, one question comes up again and again:
"How much do I actually need?"
Buying too little can mean running out unexpectedly. Buying too much might feel wasteful (unless you’re storing it properly).
So here’s a quick guide based on common UK use cases — plus tips on how to buy smart based on your needs.
🔗 Browse our full range of distilled water sizes →
📦 Common Uses & Average Monthly Water Needs
1. CPAP Machine (Sleep Apnoea Device)
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Daily use: ~300–400ml per night
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Monthly estimate: ~10–12 litres
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🔁 If you forget to refill, it can damage the unit or affect sleep quality
📌 Recommended: Buy 5L bottles or 2–3 packs here →
2. Steam Iron
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Typical session: 300–500ml
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Weekly use (light): ~2 litres
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Monthly (frequent ironing): 6–10 litres
📌 Recommended: Shop single 5L or multipack bundles →
3. Humidifier or Facial Steamer
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Room humidifier: ~300–600ml per night
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Desk steamer or diffuser: 50–100ml per session
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Monthly estimate: 5–12 litres
💡 Prevent limescale with our humidifier-safe distilled water →
4. Car Battery (Lead Acid)
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Top-ups vary by battery size
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Estimate: 1–5 litres every 3–6 months
📌 Order a 5L bottle to keep on hand →
5. Aquarium (Top-Offs or Water Mix)
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Small freshwater tanks: 5–10 litres/month
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Reef/saltwater setups: 25–100+ litres/month
🧪 View 25L and bulk sizes for aquarium use →
6. Cosmetics or Skincare Mixing
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Used in DIY mists, serums, creams
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Most home users: 1–2 litres/month
📌 5L bottles are perfect for skincare applications →
7. Commercial or High-Volume Use
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Labs, food production, manufacturing:
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100–1000+ litres/month depending on process
📦 Order 1000L IBC tanks or multiple 25L drums →
🧠 Quick-Use Summary – At a Glance
CPAP Machine
▪️ Monthly Use: 10–12L
▪️ Suggested Product: 5L multipacks
Steam Iron
▪️ Monthly Use: 5–10L
▪️ Suggested Product: Single or 3-pack 5L
Humidifier
▪️ Monthly Use: 6–12L
▪️ Suggested Product: 5L or 25L
Car Battery
▪️ Monthly Use: 1–5L
▪️ Suggested Product: 5L single
Aquarium
▪️ Monthly Use: 10–100L+
▪️ Suggested Product: 25L or 1000L
Skincare / Cosmetics
▪️ Monthly Use: 1–2L
▪️ Suggested Product: 5L bottle
Industrial Use
▪️ Monthly Use: 100L+
▪️ Suggested Product: IBC tank
🔄 Why It’s Worth Buying in Bulk
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💷 Save money: Our multipack pricing offers major discounts per litre
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🚚 Free next working day delivery across the UK
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📦 No stockouts: Always have distilled water on hand
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🌱 Eco bonus: Less packaging waste when you buy larger formats
🔗 Shop bulk or multipack distilled water now →
🧪 Not Sure What You Need?
If you're unsure how much to order, our team is happy to help. Just tell us how you're using it, and we’ll guide you to the right format — from 5L bottles to industrial IBC tanks.