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Berkeley Disaster Preparedness Neighborhood Network

Water

Water is the number one supply you need in an emergency. Store it before a disaster, keep it drinkable, and know how you would get more if the tap stays dry.

Adapted from East Bay Municipal Utility District’s July 2026 presentation to Lamorinda CERT, plus local storage guidance. Berkeley is in EBMUD’s service area.

Do this first

Sign up for water alerts now, and check them after an event. EBMUD will post outages and boil-water notices as the system comes back.

EBMUD alerts AC Alert

Water may not be available

EBMUD has redundant treatment plants, many ways to move water through the system, and crews who will respond. Even so, a major event can leave parts of the East Bay without potable water.

  • A large earthquake is likely to cause thousands of pipe breaks. EBMUD already repairs about a thousand breaks a year; thousands in one day would overwhelm crews.
  • Help will arrive through mutual-aid agreements, and the system will come back piece by piece, area by area.
  • Until then, water may not be served everywhere, and water that is in the pipes may not be safe to drink.

Systemic failures can happen! For example: a broken underground valve in Los Angeles in August 2025 left about 9,200 people without water or under a boil-water order for about a week. After the January 2025 Los Angeles wildfires, thousands were out of water or under a do-not-use order for about a month.

How much to store

Local and federal numbers differ. Treat EBMUD’s recommendation as the Berkeley target, and FEMA/CDC as a floor.

EBMUD · Berkeley target

2 gallons

per person per day, for 7 days. Don’t forget pets.

FEMA

1 gallon

per person per day, for several days

CDC

1 gallon

per person per day, enough for 3 days

Do not ration drinking water. Drink what you need, then look for more. Store extra if you can, including a little for neighbors.

Storing water

Store water before the emergency. Use it when nothing comes out of the faucet. Fill containers with potable water now, then keep that water potable.

Containers and location

  • Use food-grade containers meant for long-term storage. Do not reuse milk jugs (they are hard to sanitize). Thoroughly washed soda bottles are a short-term option; they are not designed for years of storage.
  • Keep stored water cool and dark. Opaque containers discourage algae.
  • Place containers near a faucet (so they are easy to fill) and somewhere you can dump water when you rotate it.
  • Think about earthquakes: will drums roll downhill, or will something fall on them? On a slope, consider chaining large drums to something solid.
  • Water is heavy: 1 gallon weighs more than 8 pounds. A 55-gallon drum weighs more than 450 pounds full. Pumping or gravity flow is easier than moving a full container.
  • If you store drums in a garage with gasoline, paint thinner, or other hydrocarbons, keep the drums up off the floor so spills cannot attack the plastic.

Common storage sizes

Container About how heavy full
55-gallon drum more than 450 lb
30-gallon drum about 250 lb
5-gallon carboy / jug about 40 lb
3.5-gallon stackable “brick” about 30 lb
12-ounce emergency cans portable; good for a go-kit

Avoid single-use plastic water bottles for long-term storage. Commercially bottled water past its labeled date can still be used for washing. For large drums, plan on a hand pump, spigot, or siphon pump so you can get water out without moving the container. Store the wrench, pump, and spigot indoors, near the drums, where you can still reach them after a quake.

Lamorinda CERT periodically sells food-grade drums and accessories to East Bay residents — see their water drum page and water FAQs.

Keeping stored water drinkable

  • EBMUD tap water is already disinfected (chloramine), but it is not sterile. Unless the water is factory-sealed, change it out about twice a year. Water the garden with what you discard.
  • If you use untreated well water or reverse-osmosis water, follow product directions for preservation tablets or bleach, and still rotate it. Use only plain unscented bleach whose main ingredient is sodium hypochlorite — no scents, gels, “color-safe,” or “non-chlorine” bleach.
  • For official emergency-disinfection amounts, use the EPA emergency disinfection guide. A common household rule of thumb from EBMUD is ½ teaspoon of plain bleach in 5 gallons, with contact time before drinking.

Water from your water heater

A typical home water heater holds about 30 to 60 gallons. After a major earthquake, treat it as a possible drinking-water source — and shut the house off from city water first so ruptured sewer lines cannot contaminate what is still in the tank.

  1. Turn off power or gas to the heater (circuit breaker for electric; gas valve to Off). An empty tank with the heat still on can be damaged.
  2. Close the cold-water supply valve to the tank, and shut off the house water at the street valve (usually near the front walkway). Assume sewer lines are broken after a serious quake. Avoid using taps, toilets, and drains until you know the system is safe.
  3. Let the tank cool if it was recently heating.
  4. Open a hot-water faucet somewhere in the house so air can enter the tank while you drain it.
  5. Drain from the valve at the bottom of the tank. A short garden hose or washing-machine supply hose often fits. Flush the valve briefly first, into a bucket, to clear debris. Use clean hose and containers.
  6. Let sediment settle in the collection container before drinking. If the heater is old or corroded, filter or boil the water. Mineral sediment is usually harmless; jelly-like residue can appear if the tank has an aluminum anode.

Print a copy of these steps and keep it next to the heater. Factory drain valves clog easily in hard-water areas; a ball-valve drain is less likely to fail when you need it. Full illustrated instructions: How to get emergency drinking water from a water heater.

Other indoor sources: melted freezer ice, and liquid from canned fruit or vegetables. Toilet-tank water (not the bowl) is a last resort, and only if it has not been treated with tank cleaners.

Treating water

Treat water when it is available but may not be safe to drink. Watch public notices. Do not try to treat water that has been chemically contaminated — find another source. Discard ice from an ice maker and flush refrigerator water lines after an event.

Boiling

  • Works for pathogens (Giardia, Cryptosporidium, bacteria, and viruses).
  • Bring water to a full boil, then let it cool. Store it in a clean container.
  • A camp stove is fine outdoors — not inside.
  • Boiling does not remove chemical contamination.

Other disinfection methods

  • Iodine tablets — effective for viruses, bacteria, and Giardia; not for Cryptosporidium. About 30 minutes of contact time. Tablets stay stable for years.
  • Chlorine (plain bleach) — effective for viruses and bacteria; not for Cryptosporidium. See the EPA amounts linked above.
  • Chlorine dioxide — effective for viruses, bacteria, Giardia, and Cryptosporidium. Longer contact time (about 4 hours).
  • Ultraviolet (UV) pens — effective for Giardia and Cryptosporidium; not necessarily for viruses. Needs batteries; costs more.
  • Backpacking / emergency filters (Sawyer, LifeStraw, Katadyn, Platypus, and similar) — filter out pathogens. Follow the manufacturer’s instructions, and pair with disinfection if the water is especially suspect.

Outdoor sources such as rain barrels, streams, ponds, and lakes should be filtered and/or disinfected. Pool and hot-tub water is for hygiene (toilet flushing, washing), not drinking.

Getting more water after a disaster

  • Use your stored water first. NGO distributions (Red Cross and others) can take time to stand up.
  • EBMUD will try to set up fill points around the service area — often at schools or community centers with large parking lots, sometimes next to food, diapers, and formula distribution. Sites may be on remaining piped water or on tankers. They can take a week or so to appear. Water may or may not be potable; signs will say which.
  • Bring empty containers. Collapsible jugs are easy to store ahead of time.
  • Check EBMUD alerts for maps and status as areas come back online.

Further reading

Start small

You do not have to do all of this at once. Get one thing at a time and practice with it: pick a storage spot, try a small bottle of treatment tablets, or see whether you prefer a squeeze filter or a UV pen. If you can store extra, you will be in a position to help neighbors, friends, and family.