Suspected poisoning or deliberate contamination of water

Stop using the suspect supply for drinking, cooking, preparing food, brushing teeth, making ice, mixing infant formula and giving water to pets. Use protected bottled water or an alternative supply confirmed safe by your provider. If the nature of the contamination is unknown, obtain instructions before using it for bathing, cleaning or anything else. A do-not-use instruction must be followed for every use it prohibits.

Do not taste water to investigate it. A normal appearance, smell or taste does not establish safety. Do not attempt to identify or test a suspected poison with household products. Contact your water supplier, or the local authority responsible for a private supply, and state the facts. Report suspected deliberate tampering to police; use 999 for an immediate threat to life or a crime in progress.

If someone may have swallowed or been exposed to a harmful substance: The NHS advises immediate medical help. Call 999 for suspected exposure to something harmful, unconsciousness, severe breathing difficulty, seizures or stopped breathing. If you are unsure whether an exposure is harmful, seek urgent NHS advice using the service for your UK nation. Symptoms can be delayed; do not wait for several people to become ill.

While awaiting medical instructions, do not induce vomiting and do not give the affected person food or drink. Tell the call handler the source, time and possible amount of exposure if known. Do not delay care to take samples or return to a dangerous place. Preserve relevant notices or packaging if already safely available.

Treatment limits: Boiling and ordinary water disinfection kill some germs. They do not make water contaminated with fuel, toxic chemicals or radioactive material reliably safe. A jug filter, camping filter or UV device does not prove that an unknown poison has been removed.

If you only have a forwarded rumour: Check the supplier's official website or published contact number promptly. Do not publish an accusation or announce a poisoned reservoir without verified evidence. Seek a safer water source while a credible concern is assessed; lack of visible symptoms is not clearance.