To know whether a plumber or an electrician can be trusted, you only need to check 7 things before signing anything: registration as self-employed or a company, installer's licence, reviews, a written quote, public liability insurance, references and legal guarantees. Skipping just one is expensive: Spain's consumer body OCU has recorded charges of more than €400 for opening a door, four times the average market price. Here is the full checklist, point by point.
The trust checklist in 30 seconds
| # | Check | What to ask for | Warning sign |
|---|---|---|---|
| 1 | Registered as self-employed or a company | Proof of registration or tax certificate, tax number | "I haven't got the paperwork on me" |
| 2 | Installer's licence / certificate | Registered installer or company number (electricity, gas) | "You don't need a certificate for this" |
| 3 | Online reviews | Profile with reviews and photos of real jobs | No online trace and no references |
| 4 | Written quote | Signed document with tax number, measurements, timings and VAT | A verbal quote, or "without VAT" |
| 5 | Public liability insurance | Copy of the policy in force | "In twenty years nothing has ever happened" |
| 6 | Direct references | Phone numbers of recent clients | Excuses for not giving them |
| 7 | Legal guarantees | Guarantee stated in the quote and the invoice | "I am the guarantee" |
The general rule is simple: a serious professional does not take offence when you ask for paperwork. The one who takes offence is already giving you an answer.
1. Registered as self-employed or an incorporated company
This is the first check and the cheapest: it costs nothing. The OCU recommends verifying that whoever is going to do the work has a tax number, a registered address and a business bank account. If they are self-employed, ask for proof of registration or the tax authority's census certificate: they get it free in a couple of clicks, so there is no excuse.
Why does it matter? Because without declared activity there is no invoice, and without an invoice there is no guarantee and no route to complain if something goes wrong. Everything else on this list collapses if this point fails.
2. Licensed installer and certificate
With electricity and gas, not just anyone with a toolbox will do. Only a licensed company or installer can issue the CIE, the electrical certificate, which is essential to connect the supply, increase capacity or certify the installation after a renovation involving electrical changes. According to Selectra, the certificate costs between €70 and €300 (€186 on average), plus €30–40 of regional fees, and is valid for 20 years.
With gas, the same or more serious: only a licensed gas installer can touch the installation and issue the corresponding certificate. If someone offers to "sort it without paperwork", that is where the conversation ends. And if you want to know what rates are reasonable before calling, check our guide to how much an electrician costs.
3. Online reviews and previous work
Reviews are not infallible, but a profile with real ratings, photos of finished jobs and replies from the professional says a lot. Look at three things: that the reviews are recent, that they describe jobs similar to yours, and that the negative ones (everybody has some) have a reasonable reply.
Be wary of the opposite extreme: a "professional" with no trace, no photos and nobody to vouch for them. In the trades, a neighbourhood reputation has always been the best guarantee; online reviews are the modern version of the same thing.
4. A written quote, always
This is the check that prevents the most grief. A professional quote should include, according to the OCU: full tax identification, measurements by item, materials with specifications and brands, itemised labour, waste management, start and finish dates, total price including VAT, payment terms and guarantee. Signed by both parties, it has the value of a contract.
Two golden rules from the OCU: do not pay more than 30–40% up front (payments by stage, and the last one only after the final snagging) and steer clear of "without VAT": besides being illegal, it leaves you with no invoice and, with it, no guarantee and no possible complaint. In our guide to renovation quotes we explain how to compare several without losing your mind.
Photo: Kindel Media · Pexels
🛟 Need a tradesperson you can trust, available today? On Freeday you can see rated professionals available near you and talk to them directly. Download it free — App Store · Google Play
5. Public liability insurance
Public liability insurance covers material and personal damage during the work and after it is handed over (so-called post-completion liability). It is not generally required by law, but a serious professional has it, and it is not expensive: a self-employed bricklayer with €50,000 of turnover pays around €143 a year for €150,000 of cover per claim and 24 months of post-completion liability, according to a real example from Seguroscer.
Think of it the other way round: if an uninsured plumber causes a leak that floods your neighbour's flat, in practice you end up paying for that damage. Asking for a copy of the policy in force takes a minute; taking on the risk does not.
6. Direct references
Online reviews go alongside the old-fashioned approach: ask for two or three phone numbers of recent clients and call them. Ask specific things: did they keep to the timeline? Did the final price match the quote? How did they respond when something unexpected came up? That last one is the best question: every job has surprises, and that is where you see the professional.
If they can show you a job in progress or a finished one near you, better still. A good tradesperson shows off their work; the one with nothing to show is telling you something.
7. Legal guarantees in writing
Every renovation carries guarantees even if nobody mentions them. In general terms, under Spain's building act and civil code: 1 year for finish defects (paint, tiling), 3 years for faults affecting habitability (damp, insulation, services) and 10 years for structural defects. The window to claim is 2 years from when the damage appears.
The condition for being able to enforce them: having an invoice with a date, tax number and breakdown. One more reason, in case any were needed, to rule out the "without VAT" from point 4.
Where to find a tradesperson you can trust near you
The checklist works, but it has one problem: it takes time, and when you need a plumber or an electrician you do not always have any. That is why we built Freeday: an app that shows you professionals available near you, geolocated and with ratings, so you can lock in a date instantly instead of waiting days for someone to call you back.
You see who is free today or this week in your area, check their profile and reviews, and talk to them directly. The checklist in this article still applies — written quote and paperwork, always — but the hardest part, finding someone available and vouched for, the app solves for you. Before talking prices, have a look at what an electrician or a plumber costs so you can negotiate with figures.
🛟 Looking for a plumber or electrician for this week? On Freeday you can see professionals available near you, with real ratings, and talk to them directly. Download it free — App Store · Google Play
Frequently asked questions
How do I know if an electrician is licensed?
Ask for their registered installer or company number: only a licensed installer can issue the CIE or electrical certificate, which costs between €70 and €300 (€186 on average) and is valid for 20 years. If they tell you "you don't need a certificate" to sign off a rewired installation, be suspicious.
Is public liability insurance compulsory for a tradesperson?
It is not generally required by law, but a serious professional has it. It costs little (a self-employed bricklayer pays around €143/year) and without it, any damage to third parties — a leak affecting the neighbour — in practice ends up on you.
How much should you pay up front as a deposit?
The OCU recommends not paying more than 30–40% up front. The healthy approach is to agree payments by completed stage and leave the last payment until after the final snagging. Paying 100% in advance is a very clear red flag.
What guarantee does a renovation or repair carry?
In general terms: 1 year for finish defects, 3 years for habitability problems and 10 years for structural defects, with 2 years to claim from when the damage appears. To enforce them you need the invoice, so always keep it.
What do I do if a tradesperson will not give me a written quote?
Do not hire them. A signed written quote has the value of a contract and is your only defence if the final price runs away or the timeline slips. A trustworthy professional hands it over without you having to drag it out of them.
Where do I find a tradesperson I can trust near me?
On Freeday: the app shows you geolocated professionals available in your area, with ratings from other clients, and lets you lock in a date instantly. Downloading is free and there is no subscription.