"Call a plumber" has become a catch-all term in the Netherlands for anyone who does something with water, heating or pipes. In practice there are three trades that partly overlap: the plumber for water, drainage, sanitary ware and zinc work, the heating engineer for the heating system and gas work, and the installer who combines both and often also takes care of the electrics and ventilation. Who you call determines whether the right person turns up with the right tools and, for gas and refrigerants, the right certificate. This article gives you the shortest route for each job. If it concerns a leak whose cause you do not yet know, first read Leaks: which tradesperson do you call; that article helps you choose on the basis of the symptom and is not repeated here. What you may do yourself with gas and central heating is explained in may I install a gas pipe or central heating boiler myself.
Three trades, one installation company
The plumber (loodgieter, literally "lead caster") was originally the craftsman of lead and zinc: gutters, roof edges, lead flashings around chimneys. Today the plumber is above all the specialist in everything to do with water: water pipes, drains and sewers, sanitary ware and taps, water heaters and sometimes also connecting the dishwasher and washing machine. The heating engineer (cv-monteur) focuses on the heating system: central heating boiler, radiators, underfloor heating, expansion vessel, pump, thermostat and the flue, and for gas-fired appliances also the gas connection. The installer is not a separate trade but a type of company: an installation company that installs and maintains mechanical (W) and electrical (E) installations, often referred to as a W/E installer or as a "total installer", with disciplines such as central heating, sanitary, electrics, ventilation and sustainable technology under one roof. If your home still has lead water pipes, read recognising and replacing lead water pipes.
In practice, many plumbing companies are also central heating installers and vice versa; a sole trader usually covers one or two disciplines, a larger installation company all of them. That explains why for a new bathroom you have one point of contact with one company and three subcontractors with another. So for a larger job, always ask which disciplines the company carries out itself and which it outsources.
Per job: who do you call?
| Job or problem | First choice | Explanation |
|---|---|---|
| Leaking or dripping tap, broken cistern, running toilet | Plumber | Small sanitary job; often fixed within an hour. |
| Blocked drain, toilet or sewer | Plumber or drain-unblocking company | For recurring blockages: camera inspection of the sewer. |
| Rerouting or branching off a water pipe, fitting an outside tap | Plumber | Work on the drinking water installation after the water meter. |
| New bathroom: water, drainage and heating pipework | Installation company (W), or plumber plus heating engineer | Tiling and electrics are separate disciplines; one coordinator prevents gaps in the schedule. |
| Central heating boiler fault, servicing or replacement | Heating engineer with CO certification | Gas work on the appliance and the flue is legally reserved for certified companies. |
| Adding a radiator, laying underfloor heating, bleeding or balancing the central heating | Heating engineer or installation company | Balancing (on the water side) improves comfort and reduces energy use. |
| Heat pump, air conditioning or hybrid installation | Installation company with an F-gas certificate | Often together with an electrician for the consumer unit; ask about both certificates. |
| Mechanical ventilation: servicing, replacing the unit, new heat recovery (wtw) unit | Installation company (W/E) or ventilation specialist | A heat recovery unit needs periodic filter maintenance and balancing. |
| Rerouting a gas pipe, gas valve, connecting a gas hob | Gas installer or heating engineer | No certification requirement applies to the pipework itself, but it does to the appliance and the flue; choose a recognised company. |
| Gutter, rainwater downpipe, zinc or lead work | Plumber or roofer | The original plumber's work; roofers often do it together with the roof covering. |
| Extending the consumer unit, extra circuit for a hob or charging point | Electrician | No legal certification requirement, but NEN 1010 (the Dutch wiring standard) applies, and the grid operator often carries out an inspection for a heavier connection. |
If in doubt, an installation company with several disciplines is the safest first choice: it can rule out most causes itself and does not have to refer you on.
What only certified companies may do
For part of this work the choice is not free. Three rules matter to you as the client.
- Gas combustion appliances (CO certification). Since 1 April 2023, installing, repairing, servicing and commissioning gas combustion appliances, such as a central heating boiler, gas water heater or gas fire, and the associated air supply and flue may only be carried out by a company with a CO certificate (article 6.45 of the Besluit bouwwerken leefomgeving, Bbl, the Dutch Building Decree). The company works according to a recognised assessment guideline and the engineer holds a Bewijs van Vakmanschap Koolmonoxide (carbon monoxide proof of competence). The rule is explicitly also aimed at whoever has the work carried out; you can check a company in the register of gas combustion installations. Simply rerouting a gas pipe is not covered by this obligation, but it is no job for an unqualified handyman.
- Refrigerants (F-gases). Anyone working on heat pumps, air conditioners or refrigeration systems containing fluorinated greenhouse gases, and nowadays also natural refrigerants, must be certified: the engineer with a personal certificate and the company with a company certificate (in the Netherlands via BRL 100 and BRL 200). This applies to installation, servicing, repair, leak checks and decommissioning. So when you get a quote for a heat pump or air conditioning, ask about the company's F-gas certificate.
- Electrics. There is no legal certification requirement for work on the electrical installation in homes, but the installation must comply with NEN 1010, and the part before the main switch is the domain of the grid operator. A heat pump or charging point often needs a heavier connection or an extra circuit; choose an electrician who coordinates this with the grid operator. What you may and may not do yourself is explained in May I do my own electrical work?.
In addition, there are voluntary accreditations, such as the InstallQ accreditation (the Dutch installation-sector quality body) per discipline, visible in the register at echteinstallateur.nl, and membership of the trade association Techniek Nederland, which gives you access to the Geschillencommissie Installerende Bedrijven (the disputes committee for installation companies). These are not legal requirements, but they are a verifiable sign of competence.
Emergency or planned?
Not every fault is an emergency, and the difference often saves you an evening or weekend surcharge. A genuine emergency is: water that keeps flowing after you have closed the main stopcock, water near electrics, sewage coming back up, a smell of gas (leave the house, call the grid operator's national emergency number and do not use any switches) and a central heating boiler that fails during frost in a house with young children or elderly people. Can wait until the next working day: a dripping tap, a slow-draining sink, a boiler that occasionally shows a fault code but works again after a reset, a radiator that does not get warm while the rest do. Schedule it: periodic boiler servicing, replacing a boiler that still works, a new bathroom, underfloor heating or a heat pump. For servicing and replacement you have time to compare quotes and check certificates; in an emergency you do not, and that is exactly where unreliable emergency firms strike. ACM ConsuWijzer (the consumer information service of the Dutch competition and consumer authority) advises checking the KvK (Chamber of Commerce) number and the address even in an emergency, asking for a price indication in advance and realising that the top search results are often paid adverts. How to recognise a reliable company is explained in How to recognise a reliable plumber.
What to have ready before you call
Good preparation makes the phone call shorter, the diagnosis better and increases the chance that the engineer brings the right part.
- Photos and a short video. Of the location of the problem, the tap or the appliance, the rating plate and the surroundings. Send them along via the company's app or email.
- Make, type and year of manufacture of the appliance. The rating plate of the central heating boiler is usually under the cover or on the side; for a heat pump it is on the outdoor unit. Also note the fault code on the display and whether the fault comes back after a reset.
- The central heating pressure on the pressure gauge and whether you have topped it up recently; that says a lot about a possible leak.
- Where the main stopcock, the gas valve and the consumer unit are, and whether you can operate them. For a water leak: main stopcock off; for a smell of gas: gas valve off and go outside.
- What you have already done: bled, reset, used a drain unblocker, had it repaired before. Have the last servicing invoice or the guarantee certificate to hand; many manufacturers' guarantees require servicing by a recognised company.
- Practical matters: is there parking, is the crawl space accessible, will someone be home at the agreed time, and is the home rented (in which case the landlord is often responsible for the installation)?
When making the appointment, ask about the rate including call-out charges and any surcharge, the KvK number and, for gas or refrigerant work, the certificate. Put the agreement briefly in writing or in a message. When which maintenance is due, so that you need to call in an emergency less often, can be found in the Maintenance calendar for your home.