how many liters are for brushing teeth for 15 min

Quick answer

If you leave the tap running while brushing your teeth for 15 minutes , you’ll use roughly 90 liters of water —assuming a typical modern faucet flow of about 6 liters per minute.

How the math works

Faeset flow rates vary by faucet age and design, but public water‑conservation guidance often uses:

• ~6 L/min for a typical bathroom tap.

• Some older or high‑flow taps can be 7–8 L/min or more.
• Efficient/low‑flow taps can be closer to 4–5 L/min.

So for 15 minutes:

• At 6 L/min :

6 L/min×15 min=90 L6\text{ L/min}\times 15\text{ min}=90\text{ L}6 L/min×15 min=90 L

• At 4 L/min (efficient tap): ~60 L
• At 8 L/min (high‑flow/older tap): ~120 L

That’s why sources that assume a “normal” 2–3 minute brush with the water running often quote 12–19 liters per brush , which lines up with ~6 L/min over 2–3 minutes.

Why 15 minutes is unusual (and very wasteful)

Most dental recommendations are about 2 minutes of brushing, twice a day. Brushing for 15 minutes:

• Wastes a lot of water (tens to over a hundred liters in one go).
• Can irritate gums and enamel if done aggressively or too often.
• Doesn’t meaningfully improve cleaning beyond good 2‑minute technique.

If you’re thinking of long brushing for a specific reason (e.g., orthodontic care, special medical advice), it’s worth confirming with a dentist, because standard guidance is much shorter.

Rough reference table

Tap flow (L/min)| 15 minutes → water used (L)
---|---
4| 60
5| 75
6 (typical)| 90
7| 105
8| 120

So under normal conditions, expect around 90 liters for a continuous 15‑minute brush with the tap on.

TL;DR: With a typical 6 L/min faucet, brushing for 15 minutes with the water running uses about 90 liters of water (roughly 60–120 L depending on your tap).

Information gathered from public forums or data available on the internet and portrayed here.