Tap water in Cambodia is not safe to drink. This applies to every city and province in the country, including major tourist destinations like Phnom Penh and Siem Reap. Visitors and locals alike rely on bottled water, filtered water, or boiled water for drinking. Understanding why the water is unsafe, and what your best options are, will help you avoid the gastrointestinal illness that sidelines many travelers in Southeast Asia.
Why Tap Water Is Unsafe
Even in Phnom Penh, where the water supply authority adopted WHO-based quality standards in the late 1990s and monitors dozens of parameters across treatment and distribution, the system has significant gaps. Testing at multiple sites around the capital has found high coliform counts, a marker for dangerous pathogens including viruses. The treatment processes in place can reduce turbidity and some bacterial contamination but are not designed to eliminate all viruses and pathogens present in the source water.
Beyond the treatment plants, aging and inconsistent pipe infrastructure means that water can become recontaminated between the facility and your faucet. Leaking joints, low pressure zones, and cross-connections with sewage lines are common problems throughout the country’s urban distribution networks.
Risks in Rural Areas
Outside the cities, the picture is worse. Many rural communities depend on groundwater from wells, and a significant portion of that groundwater is contaminated with naturally occurring heavy metals. About 33% of sampled groundwater sites in Cambodia exceeded the WHO guideline for arsenic, with concentrations reaching nearly 700 parts per billion in some locations. The WHO limit is 10 parts per billion. Kandal and Prey Veng provinces, both in the Mekong floodplain south of Phnom Penh, have some of the highest arsenic levels recorded.
Lead concentrations in groundwater across four provinces along the Mekong also exceed WHO drinking water limits. These metals leach from the geological formations underground and accumulate in well water over time. Unlike bacteria, boiling does nothing to remove arsenic or lead. Long-term exposure causes skin lesions, organ damage, and increased cancer risk, a condition known as arsenicosis that is already documented in Cambodian communities.
Agricultural runoff adds another layer of contamination. A screening of surface water and soil along the Mekong River in Cambodia detected 56 different pesticides in the water, with some posing severe ecological risk. While the direct health impact of these trace pesticide levels on humans from short-term exposure is lower than the microbial risks, it reinforces why untreated surface water and shallow wells should be avoided entirely.
Waterborne Diseases to Know About
The most common illness travelers get from contaminated water in Cambodia is acute diarrheal disease, caused by bacteria like E. coli and Vibrio cholerae or by rotavirus. Cholera outbreaks occur in relatively frequent cycles and are strongly linked to seasonal rainfall and temperature changes. Beyond standard stomach illness, Cambodia’s water can carry typhoid fever, leptospirosis (spread through water contaminated with rodent urine), and schistosomiasis (a parasitic infection from freshwater snails). Hepatitis A and E also spread through contaminated water.
For travelers, the practical risk is highest with casual exposure: swallowing water while swimming in rivers or lakes, brushing teeth with tap water, or eating food washed in unfiltered water. Most infections cause a few days of misery, but typhoid and leptospirosis can become serious without treatment.
Is Ice Safe in Restaurants?
This is one of the most common questions travelers ask, and the answer depends on the type of ice. Commercially produced tube or cylinder ice, the kind with a hollow center that you’ll see in bags at convenience stores and delivered to restaurants, is generally made from treated or filtered water in factory settings and is lower risk. Most mid-range and upscale restaurants, hotels, and tourist-oriented bars in Phnom Penh and Siem Reap use this factory-made ice.
The risk increases at smaller street stalls and rural eateries. A study of ice production in a neighboring Southeast Asian province found that about 52% of ice samples failed to meet microbiological standards, with E. coli detected in nearly half. The main driver was the use of untreated well water for production and poor handling at the point of sale. In Cambodia, the same patterns exist at small-scale producers. If ice looks rough, irregular, or like it was chipped from a larger block on the ground, skip it. Clean, cylindrical, factory-produced ice with a uniform shape is your safer bet.
Bottled Water and What to Look For
Bottled water is cheap and widely available throughout Cambodia, typically costing 1,000 to 2,000 riel (roughly $0.25 to $0.50) for a 500 mL bottle. Several local brands dominate the market. Vital Premium Water became the first Cambodian brand to earn international certification from NSF, a WHO collaborating center, meeting U.S. FDA and EU manufacturing standards with annual facility inspections. Other widely available brands include Khmer, Zone, and Aqua. International brands like Evian are available in larger supermarkets but cost significantly more.
Always check that the seal is intact before drinking. Refilled bottles are not common at legitimate shops, but it’s a good habit. In hotels and guesthouses, complimentary bottles in the room are standard across nearly all price ranges.
Filtering and Treating Water Yourself
If you’re traveling off the beaten path or want to reduce plastic waste, portable water treatment works well in Cambodia, but you need the right method for the right threats.
- Standard microfilters (0.2 micron pore size) effectively remove bacteria and parasites like Giardia, but they do not catch viruses, which are much smaller. Since viruses are a documented concern in Cambodian water sources, a microfilter alone is not sufficient.
- Ultrafilters (pore size below 0.01 micron) remove bacteria, parasites, and viruses. Brands like the Sawyer Squeeze or LifeStraw Mission fall into this category and provide comprehensive microbial protection.
- Chlorine tablets or drops are the WHO and CDC-recommended chemical method for field disinfection. They kill bacteria, viruses, and Giardia with adequate contact time (typically 30 minutes in clear water, longer if water is cloudy or cold). However, chlorine does not reliably kill Cryptosporidium, a parasite that causes prolonged diarrhea.
- Iodine tablets work similarly to chlorine but are recommended only for short-term emergency use by the WHO. They share the same limitation against Cryptosporidium.
- UV purifiers like the SteriPEN are effective against all microorganisms when the water is clear enough for light to penetrate. They’re compact and fast but require batteries and don’t work well in turbid water.
- Boiling kills all pathogens when water reaches a rolling boil. It’s the most reliable single method for microbial safety, though it won’t remove chemical contaminants like arsenic or pesticides.
For the broadest protection, combining an ultrafilter with either chemical treatment or UV provides redundancy. No portable method removes dissolved arsenic or lead, so in areas with known heavy metal contamination (particularly Kandal and Prey Veng provinces), bottled water from a certified source is the only reliable option.
Practical Tips for Staying Healthy
Use bottled or filtered water for brushing your teeth. It’s easy to forget this at the hotel sink, and it’s one of the most common ways travelers accidentally ingest tap water. When eating street food, stick to dishes that are freshly cooked at high heat. Raw salads and fresh fruit that you didn’t peel yourself carry more risk because they may have been washed in tap water.
Freshly squeezed juices and smoothies at market stalls often include tap water or unverified ice. If you want fruit shakes, choose vendors that visibly use sealed bottled water or factory ice. Coffee and tea made with boiled water are generally safe, since the boiling process handles the microbial risk.
Swimming in the Mekong River, Tonle Sap Lake, or rural waterways carries a real risk of leptospirosis and schistosomiasis, especially if you have any open cuts or scrapes. Chlorinated hotel pools are fine.