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200 gallon water tank: a tall reserve for a small footprint

By the Plain Prepper editors. Updated 2026-10-15.

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Quick answer

A 200 gallon tank holds 50 days of CDC's minimum 1 gallon per person per day for a family of four, on a footprint just 30 inches across. Norwesco's 200 gallon black vertical tank stands about 6 feet tall, but it is made at one California plant and sold through distributors, so check local supply first. If height is a problem, Norwesco's 220 gallon tank is wider and lower. Rotate stored tap water every six months and keep the tank cool, dark and away from chemicals.

How long 200 gallons lasts

CDC says to store at least 1 gallon of water per person per day for 3 days, and to aim for a 2-week supply if you can. It also suggests storing more for pregnant women, people who are sick, pets and hot climates.

Household	Gallons per day at CDC minimum	Days from 200 gallons
1 person	1	200
2 people	2	100
4 people	4	50
6 people	6	About 33

The CDC two-week target for a family of four is 56 gallons (4 x 1 x 14). A 200 gallon tank covers that more than three times over, which leaves room for washing, cooking and the extra needs CDC lists. Those days are a planning floor at the minimum rate, not a promise that water lasts that long in real use.

Compare the shapes before you buy

Norwesco makes three black or dark green vertical water tanks near this size. The choice is mostly about floor space and height.

Capacity	Diameter	Overall height	Fill opening	Made at
165 gallon	31 in	56 in	16 in	Several plants
200 gallon	30 in	72 in (drawing: 70 1/2 in)	8 in	Hanford, CA only
220 gallon	42 in	44 in	5 in	Several plants

The 200 gallon tank has the smallest footprint of the three at 30 inches across, so it suits a closet corner, a narrow side yard or a garage bay. Its height is the trade-off. Norwesco's product table lists 72 inches overall, while its own drawing shows 70 1/2 inches; measure your space against the taller figure.

The 220 gallon tank holds a little more and stands only 44 inches tall, but needs 42 inches of floor. The 165 gallon tank is a middle option with a large 16-inch fill opening that is easier to clean through.

Availability and what comes with the tank

Norwesco sells only through distributors, not directly. Its availability key lists the 200 gallon black and California green tanks only at the Hanford, California plant. Buyers far from the West Coast may find the 165 or 220 gallon tanks, which several plants make, easier to get and ship.

Read the fittings carefully. Norwesco notes that the 200 gallon tank includes one 2-inch bottom fitting only, with an 8-inch fill opening and no top fitting listed. Plan the valve, hose and any vent you need as separate parts, and choose drinking-water-safe components.

Norwesco's water tanks carry a three-year warranty from the date of manufacture, limited to the tank itself. The serial number is usually embossed near the fill opening.

Set it up so it stays safe to drink

Norwesco says its black and dark green water tanks are made from resin meeting FDA specifications for potable water, and that the dark color limits light and reduces algae growth. NSF/ANSI 61 certification is handled plant by plant, so ask the distributor whether your exact tank carries it.

These tanks are rated for liquids up to 9.2 pounds per gallon, which Norwesco says means water storage only. Never use one for chemicals or fertilizer, and never reuse a tank that held them. At that rated density, 200 gallons of contents would weigh up to 1,840 pounds (200 x 9.2); water is lighter than the rating, but plan the base for a load in that range plus the tank itself, on a level surface.

CDC's storage advice applies at tank scale too: label the water with the fill date, replace stored tap water every six months, keep it between 50°F and 70°F where possible, keep it out of direct sunlight and away from gasoline and pesticides, and use a clean scoop or tap rather than hands to draw water.

Heat, freezing and placement limits

Norwesco gives three limits that decide where the tank can live:

• Heat. Polyethylene tanks have a maximum content temperature of 120°F. Hotter contents, even briefly, can weaken and deform the tank.
• Freezing. The tank has no minimum temperature rating, but if water may freeze, leave room for expansion. The bulkhead fitting is the most likely place to crack.
• Burial. An above-ground tank cannot be buried; soil pressure will collapse the walls. Use a below-ground cistern instead.

The resin is UV stabilized, but Norwesco says sheltering the tank or keeping it indoors prolongs its life. A garage or shed spot that stays cool also helps meet CDC's temperature range.

What to look for when you buy

Questions people ask

How long will a 200 gallon water tank last?

At CDC's minimum of 1 gallon per person per day, 200 gallons lasts one person 200 days, two people 100 days and four people 50 days. Washing, cooking and hot weather will shorten that.

How often should I change the water in my tank?

CDC says to replace stored water every six months if you filled the containers yourself, and to label the storage date.

Can I keep a water tank outside?

Yes, but Norwesco says sheltering it or keeping it indoors extends its life, the contents must stay under 120°F, and freezing water needs room to expand. CDC recommends keeping stored water out of direct sunlight.

Is a black water tank safe for drinking water?

Norwesco says its black and dark green water tanks use resin that meets FDA specifications for potable water, and the color reduces algae. Ask your distributor about NSF/ANSI 61 certification for your specific tank.

Sources

• Black or dark green vertical water tanks: sizes, fittings, availability key, Norwesco
• 200 gallon vertical tank drawing: 30 in diameter, 70 1/2 in height, Norwesco
• Above ground tank FAQ: warranty, FDA resin, NSF 61, 120°F limit, freezing, burial, Norwesco
• How to create an emergency water supply: amounts, containers, rotation, CDC

Sources checked 2026-10-15.