Complex topic …

Whole-house water filter

Do I need a water filter at the main water line?

This question delves into a complex topic, as it may involve not only your personal preferences but also potential legal requirements. But what options are there for installing a water filter at the main water line? What are the pros and cons of the different solutions? Is installation recommended? And how does such a water filter impact your drinking water quality? In this blog article, we’ll explore these questions to help you form a well-informed opinion.

What filtration options are available for the main water line?

First, it’s important to distinguish between two categories: mandatory and optional filters. Since 2012, DIN standards 1998 and EN 806 have required the installation of a water filter in new buildings with metal pipes. This filter, often referred to as a filter cartridge due to its appearance, is a physical particle filter that removes coarse impurities and suspended solids from the water. In addition to this, you can also opt to install a more comprehensive filtration system voluntarily. Such systems typically operate on the basis of ion exchange or reverse osmosis. These two methods work in entirely different ways, so we will examine the effectiveness of each system separately in the following sections.

Why do I need a more comprehensive Filtration System at the Main Water supply?

A comprehensive water filtration system installed directly at the main water supply is generally not intended for drinking water treatment. Instead, installing a water softening system at the main water connection primarily serves to protect your household appliances. As the name suggests, such a system is designed to remove calcium from the water. When water is heated, calcium tends to adhere to surfaces, leading to limescale buildup. This buildup is not only visually unappealing but can also negatively impact the functionality of your household appliances. If you want to protect your appliances and extend their lifespan, investing in such a system can be a wise decision.

How does an Ion Exchange System work?

In ion exchange, the magnesium and calcium ions present in the water are replaced with sodium ions. The water is passed through a synthetic resin (ion exchange resin) that is loaded with sodium ions. As the water flows through, sodium is released into the water, while the resin binds to the magnesium and calcium ions. This process significantly softens your initially hard water. An ion exchange system, therefore, alters the physical properties of your water. This change is reflected in measurements like pH level, electrical conductivity, and water hardness. However, because completely softened water can also cause problems, the filtered water is mixed with untreated water—a process known as “blending.” Additionally, the ion exchange resin needs to be regularly regenerated since the sodium concentration in the resin decreases over time. This is usually done by flushing the resin with a sodium chloride solution.

Is installing an Osmosis System Recommended?

The answer to this question depends on the intended use. As a drinking water system: Absolutely! As a water softening system for the main water supply: No! An osmosis system reliably removes all impurities from your water. While this might sound very positive, in practice it can quickly lead to problems. Pure osmosis water is highly acidic and thus also corrosive without further treatment. It can corrode your pipes and even leach substances from the pipes themselves, which can then accumulate in your water. This is why osmosis systems for drinking water treatment are composed of several additional components that transform the purified water into optimal drinking water for human consumption. However, since this blog post focuses specifically on water filters at the main water supply, we would advise against installing an osmosis system in this context and instead recommend investing in a water softening system.

How do these Filtration Systems affect Drinking Water quality?

In general, it’s important to note that a water filter installed at the main water supply does not replace a drinking water treatment system. This applies to both ion exchange and osmosis systems. While ion exchange increases the sodium concentration in your tap water, the purified water from an osmosis system is too acidic. However, there are ways to mitigate the negative effects of both options. Nevertheless, since the filtered and/or treated water still passes through your regular pipes, there will inevitably be compromises in drinking water quality. Both systems definitely have their merits but serve entirely different purposes. If it’s not an option for you to install both a water softening system at the main supply and an osmosis system for drinking water treatment, we recommend first considering how you plan to use the filtration system. Which filtration solution is truly the most appropriate for your situation depends on your specific needs.