Water filter for the house connection

Table of Contents

• Why is a water filter at the house connection useful?
• Backwash filter or replaceable filter – which is right for your household?
• With or without a pressure reducer?
• Installation: What do you need to consider?
• Maintenance and operating costs
• Conclusion

A water filter for the main water supply is installed directly after the water meter in the main line – before the water reaches the faucets, water heater, or household appliances. It filters out mechanical impurities such as sediment, rust, sand, and suspended solids from the tap water, thus protecting the downstream plumbing.

Note: A main water filter is not a panacea. It removes mechanical particles – not bacteria, viruses, chlorine, or dissolved pollutants. Specialized systems such as UV disinfection systems or reverse osmosis systems are available for these tasks.

Why is a water filter at the house connection useful?

The water from the supply network in Germany is treated to meet drinking water standards – there is no doubt about that. However, deposits, rust particles, or sediment can enter the water as it travels through old pipes. Especially in older buildings or after pipe repairs in the public network, a mechanical filter at the house's water inlet is a sensible precautionary measure.

A house connection filter reliably retains the following contaminants:

• Sand and suspended solids from the supply network
• Rust particles from old pipes
• Fine metal shavings after pipe repairs
• Limescale and deposit particles

The DVGW guideline W 291 recommends the use of a fine filter immediately after the main shut-off valve to protect fittings, water meters, and water heaters. Further information on requirements for drinking water systems can be found at the German Technical and Scientific Association for Gas and Water (DVGW) .

Backwash filter or replaceable filter – which is right for your household?

There are basically two types of house connection filters:

Replaceable filter (disposable cartridge)

The filter element is completely replaced after its service life – usually every 6 to 12 months. It's inexpensive to purchase, but involves long-term maintenance.

Backwash filter

The backwash filter is self-cleaning: By reversing the flow direction, the filtered particles are flushed out without the need to replace the filter element. This saves time and operating costs. For single-family homes, we generally recommend a backwash filter – ideally with an automatic backwash function.

With or without a pressure reducer?

In many households, the water pressure exceeds the recommended operating pressure of 3–4 bar. Excessive pressure puts constant strain on fittings, seals, and household appliances. A combination of a backwash filter and a pressure reducer solves both problems in one step: The filter retains dirt particles, while the pressure reducer ensures a constant, gentle operating pressure.

Alfiltra offers exactly this combination – as a compact unit directly for home connection:

• 1" water filter with pressure reducer – backwash filter and pressure reducer combined

Installation: What do you need to consider?

The installation location is standardized: immediately after the water meter, before all other appliances. Installation should be carried out by a qualified professional, as any work on the main water line must be performed professionally according to DIN 1988.

Upon request, Alfiltra will handle the complete installation through certified specialist companies – nationwide. Information about our assembly service can be found here .

Maintenance and operating costs

A backwash filter is virtually maintenance-free. An annual visual inspection and checking the filter glass for deposits is recommended. With automatic backwash filters, the system handles the cleaning itself – optionally controlled by a timer or differential pressure.

Depending on water quality and manufacturer's instructions, replacement filters should be changed every 6 to 12 months. The replacement process usually takes less than 10 minutes and requires no tools.

Conclusion

A water filter for your main water supply is a simple and long-lasting way to protect your entire home's plumbing system. It reliably removes sediment and rust, extends the lifespan of your fixtures and appliances, and can be installed in just a few hours. If you also have high water pressure, you should opt for a combination filter and pressure reducer.

If you have any questions about choosing the right filter for your home, we will be happy to advise you personally.