Reverse Osmosis at Home: Replace Bottled Water for Good
Anyone who has so far been lugging drinking water in bottles can permanently replace the crate with a permanently installed treatment system. A reverse osmosis system (RO system) treats tap water directly at the draw-off point so that it can match high-quality bottled water in terms of taste and hygiene – without transport, without single-use waste and with significantly lower running costs. This guide is aimed at installers and technically minded end customers and explains how the technology works, what matters when it comes to sizing and assembly, and how to select the right system.
How reverse osmosis works in the home
In reverse osmosis, tap water is pressed under pressure through a semi-permeable membrane. This membrane retains dissolved salts, heavy metals, pesticide residues and a large proportion of organic impurities, while purified water reaches the other side. The retained substances are flushed into the drain with the concentrate.
In practice, a system works in several stages. A sediment pre-filter retains rust and particles, an activated carbon block removes chlorine and thus protects the sensitive membrane, then comes the actual RO membrane and a final activated carbon polishing filter for the taste. The GWS systems of the AquaWave Classic (5-stage) and AquaWave Pro G500 series map out precisely this sequence of stages. An overview of all systems, membranes and storage tanks can be found in the category Reverse Osmosis.
Tank storage or direct flow
Two design principles dominate. Classic systems such as the AquaWave Classic or the compact AquaWave Premium with an integrated 8-litre storage tank fill a reservoir from which the water is drawn off immediately when needed. This is inexpensive and completely sufficient for typical households with 75 GPD (up to around 280 litres per day).
Direct-flow systems such as the AquaWave Pro G500 with 400 GPD (around 1,500 litres per day), on the other hand, deliver water continuously without a tank and are suitable for higher demand – for example in medical practices, cafés or large households. Here an automatic flushing function and dry-running protection ensure a long membrane service life.
Why switching to domestic water pays off
- Costs: after the purchase, only costs for periodic filter changes arise – a fraction of what bottled water costs over the years.
- Environment: no single-use PET, no transport, no deposit logistics. Countertop solutions such as the CounterWave are expressly positioned by the manufacturer as an alternative to bottled water.
- Taste: chlorine, odours and a large proportion of dissolved substances are reduced – noticeably so especially with coffee, tea and plain drinking.
- Convenience: fresh water comes directly from a separate drinking water tap at the sink.
Anyone who wants to start without a fixed water connection – for example in a rented home, in a motorhome or temporarily – will find in the CounterWave a portable dual-media solution that is connected directly to the tap via a diverter valve.
Minerals after osmosis
Reverse osmosis removes very thoroughly – including desirable minerals such as calcium and magnesium. Anyone who wants a fuller taste or a higher pH value can add a downstream remineralisation stage. The MineralWave pH+ from the category Filters enriches the permeate in a targeted way with calcium and magnesium and can be integrated as an additional stage into most standard RO systems.
What installers should watch for during sizing
An RO system is only as good as its installation. Decisive are the water inlet conditions: GWS systems typically require an inlet pressure in the range of about 1.4 to 5 bar as well as a water temperature between 5 and 38 °C. If the mains pressure is too low, a version with a pressure-boosting pump makes sense – the AquaWave Premium is available both with and without a pump.
The water quality at the inlet must also match the membrane. Manufacturers specify limits for TDS, hardness, iron, manganese and turbidity. Heavily contaminated water – high turbidity or iron content – should be treated via an upstream sediment filter, otherwise the membrane blocks prematurely. With chlorinated mains water, the activated carbon pre-filter is mandatory, since free chlorine attacks the thin-film membrane.
Selecting the storage tank correctly
With tank-based systems, the storage tank determines the usable amount of water. GWS RO water storage tanks are available maintenance-free from a few litres up to large containers, in carbon steel, corrosion-protected Plasteel and stainless steel. The manufacturer-specified pre-charge pressure (factory range around 0.3 to 0.5 bar) must be observed during installation, as it influences the draw-off quantity and the pressure at the tap.
Practical checklist for planning and assembly
- Check the inlet pressure and water temperature and compare with the system data; with low pressure, choose a version with a pressure-boosting pump.
- Consult a water analysis: compare TDS, hardness, iron, manganese, turbidity and chlorine with the permissible limits.
- Estimate the demand realistically: 75 GPD for households, direct flow with 400 GPD for high or commercial consumption.
- Measure the space under the sink – compact all-in-one systems with an integrated tank save room.
- Plan a separate drinking water tap and a wastewater connection for the concentrate.
- If desired for taste: provide remineralisation with a pH+/mineral filter as an additional stage.
- Define maintenance intervals: change the pre-filter and polishing filter regularly, replace the membrane depending on water quality and use.
- Use leak protection: models with an integrated leak detector and dry-running protection increase operational reliability.
Conclusion
A reverse osmosis system permanently replaces bottled water, saves costs and packaging waste and delivers great-tasting drinking water at the push of a button. Technically decisive are the correct sizing for pressure, temperature and inlet water quality as well as an appropriately sized storage tank. From the compact household system to the direct-flow system for high demand, the GWS range in the category Reverse Osmosis covers the common use cases – supplemented by suitable filters and remineralisation in the category Filters.
Practical guide: Which size for which application?
The following overview helps you to make a rough selection of a suitable reverse osmosis system and an appropriate storage tank. The decisive factors are the daily drinking water demand, the number of people in the household and the peak draw-off (i.e. how much water is needed simultaneously or within a short period). The values given are an initial guideline based on the GWS AquaWave series – not a binding system design.
| Typical application / household size | Recommended size range (guideline) | Note |
|---|---|---|
| Single tap point, 1–2 people (e.g. apartment, single household) | GWS AquaWave Classic or Premium 75 GPD (~280 L/day) with a small storage tank (approx. 2–10 L) | Usually sufficient for pure drinking and cooking water at a single draw-off point; the tank buffers short peak draws. |
| Family / detached house, approx. 3–5 people | GWS AquaWave Premium 75 GPD (~280 L/day) with a medium storage tank (approx. 10–20 L) | The larger tank balances out morning and evening demand peaks when several people draw water in quick succession. |
| Large household or small commercial use (e.g. office, medical practice, gastro counter) | GWS AquaWave Pro G500 400 GPD (~1,500 L/day, direct flow), optionally with a larger storage tank (approx. 20–50 L) | Direct flow delivers higher throughput without long waiting times; a tank can additionally be kept on hand for peak draws. |
| Commercial / agricultural use with increased or fluctuating demand | GWS AquaWave Pro G500 400 GPD (~1,500 L/day) with a large storage tank (approx. 50–150 L), several units if required depending on the load profile | With many or simultaneous draw-off points, the tank size is decisive; the exact number of systems depends on the daily demand and the peaks. |
| High continuous demand (e.g. larger commercial use, multi-family/communal supply) | Several GWS AquaWave Pro G500 units and/or storage tanks up to 150 L, combined individually | A project-specific design is advisable here, as demand, pressure and peak load vary considerably – please coordinate with a specialist beforehand. |
Which combination of system and tank actually fits depends on several factors:
- Number of people and daily drinking water demand – how many litres of treated water are required per day.
- Peak draw-off – whether the water is drawn evenly throughout the day or in concentrated bursts (e.g. in the morning).
- Number of draw-off points – a single tap point or several connections used in parallel.
- Direct flow or tank operation – direct flow systems deliver immediately, tanks buffer short-term additional demand.
- Inlet water quality, water pressure and temperature – these influence the actual daily output of the system.
Important note: All figures are non-binding guideline values. The exact sizing of the suitable system and tank depends on the factors listed above and, in case of doubt, should be carried out by a specialist company or directly by GWS.
Frequently Asked Questions
Can a reverse osmosis system completely replace bottled water?
Yes. A permanently installed RO system treats tap water directly at the sink so that it is comparable to bottled water in terms of taste and hygiene. For typical households a 75 GPD system (up to around 280 litres per day) is sufficient; for high or commercial demand a direct-flow system with 400 GPD delivers water continuously without a tank.
Does reverse osmosis also remove important minerals from the water?
Yes, alongside contaminants the membrane also retains dissolved minerals such as calcium and magnesium. Anyone who wants a fuller taste or a higher pH value can add a downstream remineralisation stage such as the MineralWave pH+, which enriches the purified water again in a targeted way with calcium and magnesium.
What water pressure is needed for an RO system at home?
GWS systems typically work with an inlet pressure in the range of about 1.4 to 5 bar at water temperatures between 5 and 38 °C. If the mains pressure is too low, a version with an integrated pressure-boosting pump should be chosen, as is available with the AquaWave Premium.
How often do the filters of a reverse osmosis system need to be changed?
Sediment and activated carbon pre-filters are usually changed several times a year depending on water quality and use, while the RO membrane lasts considerably longer. An upstream activated carbon filter protects the membrane from chlorine and extends its service life. Exact intervals depend on hardness, turbidity and consumption.
Do I need a storage tank for a reverse osmosis system?
Not necessarily. Tank-based systems fill a reservoir from which water is drawn off immediately, and are inexpensive and sufficient for households. Direct-flow systems manage without a tank and deliver continuously – ideal for high demand or little space. Storage tanks are available in carbon steel, Plasteel and stainless steel.