How to choose a home water supply: well, borehole or surface source?
How to choose a home water supply system: well, borehole or surface source?
The decision to install your own water supply system is one of those where a wrong choice will hurt you for a long time – and not cheaply. Over the years of practice, I have seen dozens of households where the owner bought a water pump almost at random, because "the neighbor has the same one" or "the seller recommended it". The result was either a pump that could not draw water from the depth of the borehole, or on the contrary, an oversized unit that was expensive to operate, noisy and broke down every three seasons. This article will give you the basics to make the decision yourself – systematically, with an understanding of the connections.
The key decision does not depend on the price or brand. It depends primarily on what water source you have. A well, a borehole and a surface source (lake, stream, retention pond) each require a different solution. Let's look at each source in detail and also at specific recommendations for the water supply system.
Well: when is it ideal and what you need to know about it
A dug well is the oldest type of water supply and in many parts of Slovakia it still forms the basis of garden, chalet and family house water supply. Its main characteristic is a large diameter (typically 80 to 150 cm, sometimes more) and relatively small depth – usually 3 to 15 meters, occasionally up to 20 meters. The water in the well comes from the first or second aquifer, which has a decisive influence on its quality and the choice of pump.
Whenever I come to a job at a well, I always ask three things: the depth of the water level from the surface, the total depth of the well and the diameter of the shaft. These three numbers determine almost everything. If the water level is, for example, 4 meters below the surface and the well is 8 meters deep, you have 4 meters of water column in the reservoir. That is a decent reserve. If the water level is 7 meters and the well is 8 meters, you are working with only one meter of reserve – in a dry summer this can be critical.
Well capacity – yield as a key parameter
The yield of a well is the amount of water that flows into it from the surroundings per unit of time. It is usually expressed in liters per hour (l/hour) or liters per minute (l/minute). For a typical family of 3–4 people, you need at least 500–800 liters per hour, ideally more. The yield of a well can be determined by a simple test: pump out the water and measure how many minutes it takes for the level to equalize again. If 100 liters are replenished in 10 minutes, you have a yield of 600 l/hour – sufficient for a typical family home.
Problems arise with weak wells with a yield below 200 l/hour. There, it is not enough to choose the right pump – you need to solve the accumulation (a larger pressure tank, or possibly a separate storage tank). This is a topic we continue in the article Pressure tank in a home water supply system: what it is for and how to set it up?
What type of pump for a well?
For a dug well with a diameter over 80 cm, you have two main options: a surface pump (suction unit) placed outside the well, or a submersible pump lowered directly into the water. Each solution has its place.
Surface pump is cheaper, easier to service and you can keep it in the technical room. However, it has a crucial limitation: the maximum suction height is physically limited to about 7–8 meters (in practice reliably about 6–7 m). If the water level is more than 6 meters below the pump, the surface solution does not work reliably. More about this comparison can be found in the article Surface vs. submersible water pump: which is better for my water source?
Submersible pump is placed directly in the water, so the suction problem is eliminated. For wells with a diameter over 80 cm, you can use submersible pumps of larger diameter (4" and more) or special compact models 3". For most domestic wells, the 3" models are suitable – for example, home water pump with submersible pump 3 SQIBO – 0.55 / 50 l for drinking water into the well, which is dimensioned precisely for this type of source and certified for contact with drinking water.
Drilled well: deep water, different rules of the game
A drilled well is technically a completely different category. We are talking about depths from 20 to 150, sometimes even 200 meters or more, with a diameter of usually 3" (76 mm), 4" (102 mm), or 6" (152 mm). The water from a drilled well comes from deep aquifers, which has one major advantage: it is microbiologically much cleaner than water from a dug well and less dependent on rainfall and seasons.
A drilled well is realized by a professional company with the appropriate permit – it is not a DIY project. The price ranges from approximately 3,000 to 10,000 € or more, depending on the depth, geological conditions, and location. After the drilling work is completed, you will receive a report documenting the depth of the well, the diameter of the casing, the depth of the water level, and the yield. These data are crucial for selecting a water pump system.
Well diameter and pump selection – narrow tolerance
The most common mistake when selecting a submersible pump for a drilled well is underestimating the diameter. The pump must be 10–20 mm smaller than the diameter of the well casing in order to fit at all, and it must have enough clearance for water circulation (motor cooling). For a 3" well (internal diameter of the casing approx. 74–80 mm), 3" pumps are suitable – their outer diameter is typically 68 mm. A 3" or 4" pump can be installed in a 4" well (internal diameter 100 mm). Detailed dimensions and tolerances are covered in the article What well or well diameter do I need for a 3" submersible pump?
For 3" wells, a suitable option is, for example, the home water pump system with a 3 SQIBO submersible pump – 0.75 / 50 l for wells and drilled wells with a higher power of 0.75 kW, which is relevant for deeper wells where you have to overcome a greater lift height. If the depth exceeds 30–40 meters, such performance is not a luxury, but a necessity.
Discharge head and pumping head – calculation for a drilled well
This is where many people make a mistake. The pump's discharge head must cover:
- Depth of suction – the distance from the water level in the well to the surface (e.g., 25 m)
- Building lift height – from the point of entry into the house to the highest point of use (e.g., 8 m)
- Required operating pressure – typically equivalent to 20–30 m of water column (2–3 bar)
- Friction losses in the piping – depends on length, diameter, and material, roughly 10–15 % of the geometric height
In practice: a 30 m deep well with a water level at 20 m, a house on flat terrain, the highest tap 6 m above ground, required pressure 2.5 bar → the required pumping head = 20 + 6 + 25 + losses ≈ 55–60 m. The pump must be selected so that it still has this head available at the required flow rate (e.g., 2 m³/h). A detailed calculation procedure is in the article What pump power do I need for a home water pump system?
Pump protection in a drilled well – what must not be missing
A submersible pump in a drilled well operates in an environment to which you have no direct access. Therefore, the system must include several protective elements:
- Check valve on the pump's discharge port – prevents backflow of water and "column drop" when the pump is turned off
- Dry-run protection – a sensor or float that turns off the pump when the water level drops below the minimum
- Pressure switch with adjustable settings On/Off (e.g. 1.5/3.0 bar)
- Pre-filter at the pump's inlet – captures coarse mechanical impurities from the well
An RTS (Relay – Thermal protection – Switch) set integrates these functions. For example, the home water pump system with a submersible IBO 3 SDM24 / 50 l – RTS for wells includes a complete control electronics set including thermal protection and dry-run protection directly in the package – you will appreciate this especially when you install the water pump system yourself.
Surface source: stream, lake, catchment tank
A surface source is a specific category that is chosen where there is no well or drilled well – typically for cottages near rivers, in mountainous areas with a nearby stream, or for garden farms with catchment tanks for rainwater. It is the technically most complex case.
Surface water – unlike deep groundwater – is microbiologically unreliable and contains mechanical impurities, algae, sand, and organic material. Therefore, one rule applies without exception: surface water must not be used as drinking water without treatment. The system must include at least a coarse pre-filter, a fine filter, and disinfection (UV lamp or chlorination).
Pumping system for a surface source
For surface sources, a surface suction pump or a submersible pump placed in a storage tank is most commonly used. If the source is at the same or higher elevation as the pump, a suction automation in the technical room is sufficient. If the source is lower and further away (e.g., a stream 50 meters from the house), it is more advantageous to use a submersible pump directly in the source with a separate discharge pipe.
For garden irrigation systems supplied from surface tanks or wells with less clean water, the home water pump system with a submersible SCR-0.50 / 50 l pump for wells, irrigation is suitable – this solution is specifically designed for irrigation applications and can handle water with a higher content of fine impurities, which is common with surface sources.
Comparison of water sources – decision table
| Parameter | Dug well | Borehole | Surface source |
|---|---|---|---|
| Typical depth | 3–15 m | 20–150+ m | 0–2 m |
| Water quality | Medium (analysis needed! | Good | Low – requires treatment |
| Suitable pump type | Surface or submersible | Submersible 3"–4" | Surface / submersible |
| Dependence on drought | High | Low | High |
| Necessary filtration for drinking | Yes (recommended) | Depends on analysis | Always yes |
| Initial costs | Medium | High | Low–medium |
How to choose the right water pump – step by step
Once you know what type of source you have, the selection of the water pump can be narrowed down to a specific procedure. Do not make the mistake of reading the product datasheet and making a decision based solely on the power in kW – this is one of many parameters, not the only one.
Family house, 10 m well, 4 m water level – real example
Mr. Novák in a village near Trnava has a dug well 10 meters deep, with a dynamic water level at 4 meters below the surface during pumping. The house has a ground floor and a first floor, with the highest tap located 5 meters above ground. The well's yield is 700 l/hour – sufficient. The well diameter is 120 cm.
Calculation: pumping depth 4 m + house height 5 m + required pressure 2.5 bar (=25 m) + losses ~10% = total pumping head of approximately 37 m. Flow rate for a 4-person family: approximately 1.5–2 m³/hour. Solution: submersible 3" pump with a power of 0.55 kW with a characteristic covering 37 m at 2 m³/hour, pressure tank 50 liters. The result is a compact and reliable water pump system – for example, home water pump with submersible pump 3Ti-20 / 50 l – drinking water pump for well and borehole with an integrated RTS control system is ideal for this scenario.
Cottage near a mountain stream – real example
Mrs. Kováčová has a cottage in the Nízke Tatry. There is no public water supply, but 40 meters from the cottage runs a clean mountain stream. The elevation difference between the stream level and the highest tap in the cottage is 12 meters. The water is to be used for washing, flushing and partially for cooking (after filtration). Solution: submersible pump in a plastic suction pipe placed in the stream (secured with a mesh basket), PE 32 discharge pipe to the cottage, coarse pre-filter, fine cartridge filter and UV lamp. For garden applications without drinking water requirements, a model with irrigation certification will save costs.
Water quality and analysis – do not skip this step
Regardless of the type of source, it is important: before installing the water pump, have the water analyzed in an accredited laboratory. The cost of the analysis ranges from €40 to €120, which is a negligible amount compared to the cost of the entire system. A standard drinking water analysis according to the decree of the Ministry of Health of the Slovak Republic No. 247/2017 Coll. includes microbiology (coliform bacteria, E. coli, enterococci), chemical indicators (nitrates, nitrites, ammonia, hardness, pH, iron, manganese) and sensory properties.
The analysis result will tell you whether you need filtration and, if so, what type. Excessive iron requires an oxidation filter, hard water needs a water softener, microbiological contamination needs a UV lamp or dosing device. This solution is then designed as an add-on to the water system. Details on the requirements for a well water system for drinking water are processed in the article Drinking water from a well via a water supply system: what must the system and pump meet?
Pressure tank: size matters more than you think
The pressure tank is a part of every well-designed water supply system. Its role is twofold: it dampens pressure surges in the system and, above all, it reduces the frequency of pump starts. Each pump start is a load on the motor – if the pump starts 50 times per hour (which is realistically the case with a small tank), its lifespan drops drastically.
Guideline: for a family house with normal consumption, a minimum of 50 liters of effective volume is recommended, better 80–100 liters. Most water supply systems in the Atria.sk category are delivered with 50-liter tanks, which is a good basis – but if your house has more than two bathrooms or a large garden, consider an additional tank.
Installation – what is DIY and what is not
Mounting the submersible pump into the well or borehole and connecting the control unit is a task that a skilled DIY enthusiast can handle – especially if the water supply system contains a pre-assembled RTS unit with a clear instruction manual. Electrical connections (grounding, fusing, inspection) must be performed by a licensed electrician. Connecting to the house plumbing and pressure testing are also doable by yourself, provided you have experience with plumbing work.
A complete step-by-step guide can be found in the article Installation of a home water supply system with a submersible pump, step by step, where common installation errors and how to avoid them are also described.
What is always the job of a professional: drilling the borehole, modifications to the distribution panel, connection to the public network (a legal requirement to separate the systems), and inspection of the electrical installation.
Operating costs and energy consumption
People tend to focus on the price of the water supply system when purchasing it, but they often forget about operating costs. A submersible pump of 0.55 kW that runs an average of 2 hours per day (a realistic value for a family house) consumes about 400 kWh per year. At a cost of 0.20 €/kWh, this is 80 € per year – which is negligible. A bigger impact on costs has the frequency of service interventions and the pump's lifespan.
A properly dimensioned pump with a sufficient pressure tank, regularly checked pre-pressure in the tank, and an annual inspection of the entire system – this is the recipe for 10–15 years without problems. The maintenance procedure is detailed in the article Maintenance and service of a home water supply system: what and how often to check?
Most common mistakes when choosing a water supply system – a summary from practice
- Underestimating the delivery head – the most common reason why a water supply system "does not work well" right from the start
- Selecting a pump based on price, not parameters – a cheap pump with insufficient delivery head will never work properly
- Too small a pressure tank – unnecessarily shortens the pump's lifespan
- No water analysis – drinking microbiologically faulty water is a health risk
- No dry-run protection – one dry summer can destroy a pump worth hundreds of euros
- Wrong pump diameter for the borehole – the pump either won't go down or it will vibrate and rub against the walls of the casing
- Forgotten check valve – with every pump start, a column of water is lost and the pump has to fill the entire pipe from scratch – wear and noise
Frequently asked questions (FAQ)
Can I use the same water supply system for drinking and irrigation water?
It depends on the pump's certification and the materials in contact with the water. Pumps designed only for irrigation do not have certification for contact with drinking water (they lack, for example, an NSF or EN 12050 certificate), and their hydraulic materials may not be hygienically suitable. If you want one system for both applications, choose a pump with certification for drinking water – it will handle irrigation without problems, but not the other way around.
What is the maximum depth for a 3" submersible pump?
The maximum depth depends on the length of the cable supplied with the pump (typically 10–30 m) and the pump's maximum delivery head (50–90 m depending on the model). The cable can be extended, but you must use a cable of the same cross-section and waterproof connectors approved for this purpose. Some models are supplied with a longer cable by default for deep boreholes. Always check that the pump's delivery head at your flow rate is higher than the pumping depth plus other losses.
What happens if the well's yield is insufficient for the pump?
The pump will start pumping air (dry run) – this causes motor overheating and very rapid pump failure. Therefore, dry-run protection is an absolute requirement, not an optional feature. In practice, protection is achieved using a float switch in the well, a pressure sensor on the discharge side, or an electronic dry-run sensor integrated into the control unit (RTS system). An alternative solution: installing a storage tank between the well and the pump, from which you draw water – in this case, the yield continuously refills the tank and the pump draws from the reserve.
Do I need a permit for my own well or borehole?
Yes, in Slovakia, a building permit (water construction) issued by the relevant building authority and approval from the river basin manager (SVP š.p.) are required to construct a well or borehole for household water supply. Exceptions apply to wells built before 1954. Operating your own well for private family use is not restricted in itself, but the water must meet hygiene standards according to the decree of the Ministry of Health of the Slovak Republic – therefore, water quality analysis is recommended especially when the source's characteristics change or when the water supply system is first installed.
Is a submersible water supply system noisy?
A submersible pump is the least noisy of all types, because the motor and hydraulics are submerged in water, which dampens the sound. If the system is properly dimensioned, you will not hear anything in the house or only a faint hum of the pipes when you open a tap. Noise can occur with insufficiently secured pipes (vibrations), with a too small pressure tank (frequent starts), or with a damaged pump bearing. If the water supply system becomes noisier than usual, it is a signal for inspection – see the article Home water supply system not pumping or losing pressure: causes and solutions.
Can I install the water supply system outdoors or in the well?
The control unit (pressure tank, pressure switch, electrical connections) must be protected from frost and direct moisture – typically in a technical room, boiler room, or insulated water supply shaft. The submersible pump itself is designed for permanent submersion in water, so it is safe in the well or borehole. The discharge pipe between the well and the house must be buried at an un-freezing depth (in Slovakia, usually 100–120 cm, more in mountainous areas).
Conclusion: a systematic approach always wins
A home water supply system is not just a pump that you throw into a well and plug into an outlet. It is a complex hydraulic system, where each component – the source, pump, pressure tank, filtration, control, and distribution – must be coordinated with the others. If you start with a clear understanding of your water source, its depth, yield, and required performance parameters, selecting a specific product is just the logical conclusion of the task.
If you are unsure about any step – from calculating the delivery head to selecting the pump diameter – go through the topics in the Knowledge Center systematically. Each of them covers a specific aspect, together forming a complete guide for every common situation you may encounter in practice. And if you run into an unexpected problem after installation, the article Frequently asked questions about home water supply systems with submersible pumps covers most of the situations reported in real customer practice.
Do you have a question on this topic?
Not sure what to choose or dealing with a specific situation in your home? Write to us – we are happy to help.