Water by tanker, cisterns and storage tanks in rural homes

Key rules

• Tank size: Hold at least 7 to 15 days of use, or one full delivery plus a reserve.
• Drinking water: Ask for potable-certified water and a potability certificate, because some tankers carry non-potable irrigation water.
• Supplier: Check the supplier is registered with the regional health authority.
• Cost: Tanker water costs many times more than mains water, so compare price per cubic metre.
• Rainwater: Roof rainwater on your own land is legal, but it must be treated before you drink it.

The short version

Without mains water, you depend on a tanker lorry filling a tank you own. Plan three things before you move in: a tank big enough to bridge delivery delays, a supplier who can reach your property and sells drinking-quality water, and a budget for running costs that are far above mains prices.

How tanker delivery works

You order from a local camión cisterna supplier, by phone or WhatsApp. Some are municipal services and some are private firms. Your town hall can tell you who serves your area.

• Load size: trucks usually carry 8,000 to 30,000 litres. Price per cubic metre falls as the volume rises.
• Lead time: usually 1 to 3 days. It is longer in summer or in a drought, so order early in those periods.
• Access: the truck needs a track a heavy lorry can use, with enough width, turning space and a clear path overhead.
• Hose reach: hoses commonly reach about 30 to 60 metres. If your tank is farther away or uphill, you may need a longer hose or a pump.

Before your first order, confirm hose length, the truck's weight limit and where the water comes from. The checklist below covers these questions.

Choosing the storage tank

Plan on about 120 to 200 litres per person per day. Four people use roughly 0.5 to 0.8 cubic metres a day. A garden or pool adds a lot.

Choose a tank that holds at least 7 to 15 days of use, or one full delivery plus a reserve. For a family this often means 5,000 to 10,000 litres. Match the size to the truck's load and to what your access road allows. The options are compared in the decision below.

Use a food-grade, opaque, covered tank. If you will drink the water, add a filter and disinfection.

Is the water safe to drink?

Not always. Some tankers carry non-potable water meant for irrigation. For drinking:

• Check the supplier is registered with the regional health authority.
• Ask for a potability certificate or a recent analysis.
• Check the load is labelled apta para consumo humano.
• Ask specifically for potable-certified water when you order.

The supplier is responsible for quality and traceability. A town hall that sends a tanker, for example in a drought emergency, is responsible for that water.

What it costs

Expect two separate costs.

Water. It is sold per load. The price depends on distance from the source, whether it is potable-certified, your region and the season, and it rises in a drought. Delivery is often included, but ask. Per cubic metre it costs many times more than mains water. Get quotes from several local suppliers and compare the price per load and per cubic metre.

Tank and installation. Small above-ground polyethylene tanks of 1,000 to 5,000 litres are the cheapest. Large buried or concrete tanks cost much more because of digging, a crane and plumbing. Installation adds a pump, a pressure vessel, filtration and a base slab, and often costs as much as the tank itself. Get a price for the whole package.

Rainwater as a supplement

Collecting rainwater from your own roof is legal and common. Collected on your own land for domestic use, it generally needs no permit. Taking runoff from a stream or ravine does need one. Some regions and towns encourage or require harvesting in new builds, for example Catalonia and the Balearics.

Rainwater is not drinkable by default. It must be treated to meet the drinking-water standard first. Most households use it for the garden, toilets and laundry. Size a rainwater tank by roof area, local rainfall and the length of your dry season. Check local rules with your town hall and the river basin authority (confederación hidrográfica).

Avoiding running dry

Reorder before the tank runs low, and leave room for a full load. The timeline below sets out the order of steps. If water or power fails at a remote home, see the "What if" section below.

Choosing between options

How big a storage tank should you install for tanker water?

• Small above-ground tank, 1,000 to 5,000 litres: Fits a small household or a low budget, and you can take frequent deliveries. This is the cheapest category.

• Mid-size tank, 5,000 to 10,000 litres: Fits a family of about four that wants one full delivery plus a reserve.

• Large buried or concrete tank: Fits a household with a garden or pool and high use. It costs much more because of excavation, a crane and plumbing.

Estimate 120 to 200 litres per person per day, then choose a tank holding at least 7 to 15 days of use, or one full delivery plus a reserve. Make sure the truck load and your road access suit that size. Price per cubic metre falls as the load grows, so fewer, larger deliveries cost less per cubic metre.

Check current prices with local suppliers and your town hall before choosing a tank size.

Timeline and deadlines

• Work out your daily water use and pick a tank that holds at least 7 to 15 days of it: before you order your first delivery

• Check the access track, hose reach and truck weight limit with the supplier: before you order

• Order a load by phone or WhatsApp, asking for potable-certified water if you will drink it: 1 to 3 days before you need it

• Order earlier in summer or in a drought: more than 3 days ahead in busy periods

• Reorder before the tank runs low, leaving room for a full load: while at least 7 days of water remain

Checklist

• Get quotes from several local tanker suppliers or ask your town hall, comparing price per load and per cubic metre.

• Ask whether delivery charges are included in the quoted price.

• Confirm hose length, truck weight limit and water source with the supplier before ordering.

• Get a price for the tank plus pump, pressure vessel, filtration and base slab, since installation often costs as much as the tank.

• Ask your local council and river basin authority (confederación hidrográfica) about rainwater rules before you collect it for drinking.

What if water or power fails at a remote home

If the water fails

Call your tanker supplier first, then switch to your reserve while the truck is on its way.

1. Switch to your reserve. Use the reserve tank (depósito) for essentials only: drinking, cooking, toilets. Keep bottled water for drinking.
2. Order a delivery. Phone or message a local camión cisterna supplier. This is often the town hall's service or a private firm. Loads are typically 8,000 to 30,000 litres. Delivery usually takes 1 to 3 days, and longer in summer or in a drought. Ask for potable-certified water if it is for drinking.
3. Check your own equipment. If you have a well or borehole, check the pump, pressure tank and filters. A pump needs power, so a power cut can also cut your water.

If the power fails

Call the distribuidora, not your electricity retailer. The distribuidora owns and runs the network.

1. Check it is not just your home. Look at the main switch and trip switches, and ask a neighbour.
2. Find the fault line. The distribuidora is named on your bill and is shown by the first letters of your CUPS, the supply point code. The CNMC has a CUPS lookup tool if you are unsure. Each of the main companies (i-DE, e-distribución, UFD, E-Redes) has a free 24-hour fault line printed on the bill. Some rural areas have a small local distribuidora instead. Use the number on your bill, because numbers differ by company.
3. Give your CUPS and address. Ask for a reference number for the report. Keep it.
4. Switch to backups. Use your backup power for the water pump first, then for refrigeration if it lasts.

What to hold before anything fails

• A reserve tank sized for several days. A common guide is 100 to 150 litres per person per day. A family of four needs roughly 2,000 to 5,000 litres or more.
• A second water source. This could be a well or borehole with a pump on backup power, or rainwater collection.
• Filtration or disinfection for any water that is not certified drinking water.
• Bottled drinking water.
• The phone numbers on paper: your tanker supplier, the town hall and the fault line from your bill. Your phone may not work in an outage.

If outages keep happening

Long or repeated cuts can earn you money back. If the distribuidora goes over the limits for hours or number of interruptions in your type of zone, it must give you an automatic discount on your bill. If a cut damaged your equipment or belongings, you can claim compensation from the distribuidora. Check the current limits and how the discount is calculated with your distribuidora.

Take your complaint to the distribuidora first, then to your retailer. If neither solves it, go to your region's consumer or industry department. Consumer arbitration is another route. Keep your report reference numbers and photos of any damage.

Frequently asked questions

Can I drink rainwater collected from my roof?

Yes, you can drink rainwater from your roof, but only after it is treated to meet the drinking-water standard. Rainwater is not safe to drink by default. Most households use it for irrigation, toilets and laundry instead.

Do I need a permit to collect rainwater on my own property?

No, collecting rainwater from your own roof and storing it for home use generally needs no permit. Diverting runoff from streams or ravines is different and does need permission. Some regions, such as Catalonia and the Balearics, encourage or require harvesting in new builds, so ask your local council.

Why might tanker water not be safe to drink?

Some tankers carry non-potable water meant for irrigation, so the water you receive may not be drinkable. Ask for water labelled apta para consumo humano and for a recent analysis or potability certificate.