Should You Run the Tap Before Drinking? The Definitive Answer

December 12, 2025 •

3 min read

According to the EPA, flushing tap water for 15–30 seconds can reduce exposure to lead that may have seeped into water from older plumbing. This is a crucial step to take before drinking tap water, especially in homes built before 1986.

Quick Summary

Running tap water for a short time before drinking improves water quality. This helps flush out stagnant water that can accumulate contaminants like lead and copper from older plumbing. It ensures the freshest, coldest water from the main supply.

Key Points

Flushing is Recommended: Experts advise running the cold water tap for 30 seconds to several minutes to clear stagnant water from your pipes before drinking or cooking.
Protect Against Lead: Running the tap is a crucial step to minimize exposure to lead, which can leach into water from old plumbing, especially in homes built before 1986.
Use Only Cold Water: Never use hot water from the tap for drinking or cooking, as it is more likely to dissolve harmful metals and minerals from your pipes and water heater.
Water Quality Varies: While municipal water is treated, the quality can be affected by your home's specific plumbing. Stagnant water can develop off-tastes and odors from pipe minerals.
Combine with Other Safety Measures: For maximum safety, consider using a certified water filter and testing your water for contaminants, particularly if you live in an older home.

The question of whether to run the tap before drinking is common. The practice is a wise precaution, especially depending on the home's age and location. While modern water treatment facilities deliver high-quality water, the journey through home plumbing can introduce factors that affect its taste and safety.

Why You Should Run the Tap

The main reason for flushing the faucet is to clear standing water from home pipes. Water that has been in plumbing for several hours, such as overnight, can accumulate small amounts of metals or other minerals. This is a concern in older houses.

Lead Contamination

One significant reason to run the tap is the risk of lead contamination from older pipes. Homes built before the 1986 ban on lead pipes and solder may still have these materials in their plumbing. As water sits in these pipes, it can dissolve lead particles. They can then end up in your drinking glass. According to the EPA, running the cold water for 15 to 30 seconds can flush out this stagnant water. For homes with a known lead service line, experts recommend flushing for 3–5 minutes.

Mineral Buildup and Taste

Beyond lead, stagnant water can also pick up other minerals that affect its taste. Rust or other deposits from older galvanized pipes can give water a metallic or off-putting flavor. Flushing the tap brings in fresh, aerated water from the main supply. This typically tastes cleaner.

Temperature and Hot Water Dangers

It is crucial to only use cold water for drinking and cooking. Hot water is more likely to dissolve contaminants. It may contain metals, sediment, and bacteria that build up in the water heater. Boiling water does not remove lead and can actually concentrate it. Running the tap until it runs noticeably colder ensures you are getting fresh, cold water.

Comparison: Tapping Immediately vs. Flushing


Feature	Drinking Immediately (Stagnant Water)	Running the Tap (Fresh Water)
Contaminant Risk	Higher risk of lead, copper, and other mineral exposure from pipe leaching, especially in older homes.	Significantly lower risk of lead and other contaminants, as stagnant water is flushed out.
Taste and Odor	May have a stale, metallic, or unpleasant taste and odor from sitting in pipes.	Tastes fresher and cleaner, as it comes directly from the treated main supply.
Temperature	Varies based on ambient pipe temperature; may be warm or lukewarm.	Runs noticeably colder as you flush out the water that has been sitting in the pipes.
Safety	Potentially unsafe for consumption, especially hot water which can dissolve more contaminants.	Safer for consumption, particularly for drinking and cooking purposes.
Efficiency	Faster, but potentially compromises water quality.	Slightly delayed, but offers peace of mind regarding water quality.

Practical Steps for Safer Drinking Water

It’s important to incorporate this habit into your routine. Here are some actionable tips:

Flush the Faucet: Before using any faucet for drinking or cooking, run the cold water for at least 30 seconds. If your home has lead service lines, a longer flush of 3–5 minutes is advised.
Use Water for Other Tasks: To avoid wasting water, use the flushed water for other needs like watering plants, doing dishes, or cleaning.
Clean Aerators: Regularly clean your faucet's screen, or aerator, where sediment and lead particles can collect.
Filter Your Water: For extra security, use a water filter certified to remove lead, such as those meeting NSF Standard 53.
Test Your Water: The only way to know for sure if you have lead in your water is to have it tested. Contact your local water utility for information on testing.

Conclusion: A Small Action for Major Peace of Mind

Running the tap before drinking is a sensible precaution that can improve water quality and safety. While the risk varies by home age and plumbing materials, flushing out stagnant water can reduce exposure to heavy metals like lead. It improves the taste and temperature of your water. By adopting this habit, along with other simple maintenance steps, you can ensure a safer drinking experience.

For more information on lead in drinking water and what you can do to protect your family, consult the U.S. Environmental Protection Agency's website for comprehensive guidelines.

Frequently Asked Questions

For homes without a lead service line, running the cold water for 30 to 60 seconds is generally sufficient. If you have a known lead service line, it's recommended to run it for 3–5 minutes.

While it's unlikely to be immediately dangerous, stagnant water from your pipes can have a higher concentration of leached metals like lead and copper. It's a best practice to flush the pipes before consuming.

Hot water dissolves contaminants like lead more quickly than cold water. It can also contain minerals and bacteria from your water heater, so you should always use cold water for consumption.

No, boiling water does not remove lead. In fact, it can cause lead to become more concentrated as some of the water evaporates. Boiling is only effective for killing biological pathogens.

Lead pipes appear dull grey and are soft enough to scratch with a coin, revealing shiny, silver-colored metal underneath. You can also contact your local water utility to check their records or have a water test performed.

To avoid waste, you can collect the flushed water for non-consumptive purposes, such as watering plants, cleaning, or flushing the toilet.

The only way to be certain of your water quality is to have it tested by a certified lab. This is especially important for households with infants or young children, as lead exposure is particularly harmful to them.