Pipes, hard water and the electric water heater (termo)

Key rules

• Hardness: Your water utility publishes local hardness, and above 180 mg/L is very hard.
• Lead limit: Lead in drinking water must not exceed 10 µg/L, and the limit drops to 5 µg/L from 2036.
• Pipe responsibility: The utility is responsible only up to the connection point, not for pipes inside the building.
• Termo size: Choose 50 litres for one person, 80 for two, 100 for three, and 120 to 150 for four or more.

Check how hard your water is

Start with your local water utility. It usually publishes hardness on its website or on your bill, and you can also ask it directly. A test strip gives a quick check at your own tap.

Hardness is given in mg/L of calcium carbonate or in French degrees (°f). As a guide:

• Under 60 mg/L: soft.
• 60 to 120 mg/L: moderately hard.
• 120 to 180 mg/L: hard.
• Over 180 mg/L: very hard.

So 150 mg/L counts as hard. Hardness changes by supply zone and season, so treat one reading as a guide. Limescale on taps, showerheads and the kettle shows how much it affects your home.

Fixes for limescale

Hard water leaves limescale in pipes, taps and your termo. The main options, from most to least thorough:

• Descalcificador: a salt-regenerated softener fitted on the main supply. It removes hardness, but needs salt and a drain connection. It costs the most to install and run.
• Anti-limescale cartridges or polyphosphate dosers: a middle option.
• Descaling products: citric acid or vinegar for appliances and taps. They are cheap but only treat the symptoms.
• Magnetic or electronic descalers: cheap, but it is doubtful whether they work.
• Reverse osmosis filter: for drinking water only.

Prices vary by brand and installer, so ask for several quotes.

Lead and galvanised pipes

Older buildings, especially those built before the 1970s or 80s, may have lead or galvanised pipes. Scratch a visible pipe lightly:

• Dull grey, soft, and shiny silver underneath, with no magnet attraction: lead.
• Grey, hard, threaded, magnetic and rusting: galvanised.

Lead is toxic, especially for children and pregnant women. Galvanised pipes corrode, which cuts flow and water quality. The lead limit in drinking water is 10 µg/L, falling to 5 µg/L from 2036.

If you suspect lead, ask the building administrator or the utility, and request a water test at the tap. Run the tap before drinking if the water has stood for a while. Replacing pipes is a job for plumbers. The utility is responsible only up to the connection point, so pipes inside the building are the building's or your own concern.

Low water pressure

Common causes are a partly closed stopcock, clogged aerators or filters, scaled or corroded pipes, leaks, a faulty pressure reducer, a weak supply on high floors, a failing building pump (grupo de presión), peak demand, or network works.

Who fixes what:

• You: open the stopcock fully, clean aerators and filters, and check valves.
• A plumber: internal pipes, reducers and leaks.
• The community administrator: shared pumps and risers, through its maintenance firm.
• The water utility: low mains pressure up to the meter.

A booster pump for your own home can be added where the community allows it.

Sizing your termo

A termo is an electric storage water heater. Typical sizes are:

• 50 litres for one person.
• 80 litres for two.
• 100 litres for three.
• 120 to 150 litres for four or more.

Plan on about 30 to 40 litres per person per day at 60 °C. With a bathtub or heavy use, go up one size. Common sizes are 30, 50, 80, 100, 120, 150 and 200 litres. This does not apply to gas instant heaters or aerothermal systems.

The checklist and questions below cover the quick checks.

Checklist

• Look up your water hardness on your water utility's website or bill, or ask the utility directly.

• Use a test strip if you want a quick check of hardness at your own tap.

• Scratch a visible pipe lightly: shiny silver underneath means lead, and a magnet that sticks means galvanised steel.

• Ask the building administrator or the water utility about the pipes if the building is older than the 1970s or 1980s, and request a water test at the tap.

• Open the stopcock fully and clean the aerators and filters on taps if the pressure is low.

• Call a plumber for leaks, scaled pipes or a faulty pressure reducer, and tell the community administrator if the shared pump or risers seem to be the problem.

• Check the termo size against the household: 50 litres for one person, 80 for two, 100 for three, and 120 to 150 for four or more.

Frequently asked questions

What size of termo do I need for a family of four?

A family of four usually needs a termo of 120 to 150 litres. A common rule of thumb is 30 to 40 litres per person per day at 60 °C. If the bathroom has a bathtub or your hot-water use is high, go up to the next size.

Is water considered hard if it measures 150 mg/L?

Yes, 150 mg/L of calcium carbonate counts as hard water, since hard runs from roughly 120 to 180 mg/L. Above 180 mg/L it is very hard. Your water utility can tell you the figure for your supply zone.

Which limescale treatment costs the least?

Descaling products such as citric acid or vinegar are the cheapest option, but they only treat the symptoms on taps and appliances. Salt-regenerated softeners (descalcificadores) cost the most to install and run, because they need salt and a drain connection. Ask several installers for quotes before you choose.