🏙 Property in Triel-sur-Seine (78510)

Triel-sur-Seine has a population of 12,206, a density of about 883 inhabitants per km². Flats sell there at a median price of €3,187/m² (2025) and are advertised for rent at around €17.6/m² per month, an indicative gross yield of about 6.6%. Between 2022 and 2025, advertised rents are up by 12.2%. The overall property tax rate on buildings (taxe foncière) is 39.36% in 2025, up by 6.57 points compared with 2021. The average reference taxable income per household is €45,650 (2024), and 63% of households pay income tax. Of the energy performance certificates (DPE) issued for flats in 2025, 6.1% are rated F or G. Triel-sur-Seine has had 15 natural disaster declarations since 1982, 6 of them for floods or mudslides. The national register lists 101 registered co-ownerships (2,794 units).

📰 Triel-sur-Seine at a glance

Département: Yvelines (78) · Region: Île-de-France

Size and profile

Triel-sur-Seine has a population of 12,206: it is one of the largest municipalities in its département, where the median is 1,302 inhabitants. Population density there is 883 inhabitants per km²: a urban or suburban profile.

Rents and prices

At €17.6/m² per month, advertised rents exceed the département median (€16.1/m²). Between 2022 and 2025, the advertised rent has risen by 12.2%, at the same pace as the median of the municipalities in its département (11.2%). The median price of flats sold is €3,187/m² (2025), below the département median (€3,670/m²).

Incomes and taxation

The average reference taxable income per household (€45,650 in 2024) is below the median of the municipalities in its département (€48,984). It has risen by 15.7% since 2018, at the same pace as the département median (16.5%). 63% of tax households there pay income tax, against 67% for the median of the municipalities in its département. The overall property tax rate (39.36%) is 10.8 points higher than the département median (28.54%).

Hazards and energy

Triel-sur-Seine has had 15 natural disaster declarations since 1982, i.e. far more than the département median (6). They mainly concern floods and mudslides (6 declarations). 3 natural risk prevention plans are in force in the municipality. Of the energy performance certificates issued for flats in 2025, 6.1% are rated F or G (median of the municipalities in its département: 4.9%).

Co-ownerships

The national register lists 101 co-ownerships (2,794 units), or about 8.3 per 1,000 inhabitants.

Points to watch before buying or renting

• The property tax rate is well above the median of the municipalities in its département: factor it into the cost of owning the property, on top of running charges.
• Several “drought” declarations have been issued: ask whether the property has had cracks and check the clay shrink-swell map (Géorisques) before buying.
• Flood risk is listed: check the risk statement for the property and, if there is one, the prevention plan attached to the local urban plan.
• Before buying into a co-ownership: ask for the minutes of the last three general meetings, the maintenance log, the amount of the works fund and the state of unpaid charges.

Summary written automatically from the figures on this page, comparing the municipality with the median of the municipalities in its département (or of France when the département has too few municipalities with data).

💶 Prices and rents: how they have changed

1,895 listings observed. These are advertised rents, service charges included: they are higher than the rents of existing leases. The estimation method was revised in 2022: only the 2022 and later editions, which are comparable with each other, are shown. The gross yield compares the annualised rent with the median sale price of flats; it takes no account of service charges, property tax or vacancy.

👥 Household incomes

Tax statistics from the DGFiP: income for 2024, declared the following year. The reference taxable income is an average: very sensitive to high incomes, it is not a substitute for a median income. The incomes are those of the tax households living in the municipality, not only those of co-owners.

🌡 Energy performance of homes (DPE)

Calculated on the DPEs issued for flats each year (310 in 2025), on sales or lettings: they do not cover the whole housing stock and reflect homes that change occupant. The years 2021 (second half only) and the current year, being incomplete, are not shown. The DPE calculation method changed (July 2021 reform), which limits comparison with earlier years. Under France’s Climate and Resilience Act, homes rated G have been banned from letting since 1 January 2025, followed by those rated F from 2028 and E from 2034.

🌊 Natural hazards

Hazards listed for the municipality:

A declaration recognises a state of natural disaster for a given event; it triggers the “natural disasters” cover of home insurance policies and of the building’s insurance. “Drought” declarations relate to the shrinking and swelling of clay soils, a frequent cause of cracks in buildings. A risk statement (état des risques) must in particular be attached to a sale or lease when the property lies in an area covered by a prevention plan, in seismic zone 2 to 5, or with a class 3 radon potential. This page presents municipal data: it does not replace the risk statement drawn up for the property’s address.

🧾 Property tax and local taxation

The overall rate adds the municipal share and the inter-municipal share. The tax due by an owner equals this rate applied to half of the home’s cadastral rental value, reduced where applicable by exemptions.

🏢 The co-ownerships of Triel-sur-Seine

Budget and arrears are declared by the managing agents to the register; outliers are discarded and the median is used. They are only available for the years in which the register publishes them.

🧑‍💼 The main professional managing agents

📊 Triel-sur-Seine compared with neighbouring municipalities

• Advertised rent: 17.6 €/m²/month, rank 7 of 9 municipalities compared, from highest to lowest (neighbours’ median: 17.9 €/m²/month).
• Median price of flats: 3,187 €/m², rank 6 of 6 municipalities compared, from highest to lowest (neighbours’ median: 3,591 €/m²).
• Average reference taxable income: 45,650 €, rank 5 of 9 municipalities compared, from highest to lowest (neighbours’ median: 45,703 €).
• Property tax rate: 39.36 %, rank 6 of 9 municipalities compared, from highest to lowest (neighbours’ median: 42.46 %).

The 8 nearest municipalities (as the crow flies, from the centre). Latest values available; “—”: data not published or too few sales. Rents are estimated for groups of municipalities: neighbours may share the same estimate. The rank compares the municipality with these neighbours, not with the whole of France.

📚 Sources and method

Each indicator comes from an open dataset that is kept over time: when a source is updated or corrected, the old value stays on record, which makes it possible to follow changes from one year to the next.

• Ministère de la Transition écologique, base GASPAR (Géorisques) — Licence Ouverte 2.0. Retrieved in October 2026.
• ADEME, base des DPE des logements existants — Licence Ouverte 2.0. Retrieved in October 2026.
• Demandes de valeurs foncières © DGFiP / Etalab — Licence Ouverte 2.0. Retrieved in October 2026.
• Carte des loyers © Ministère de la Transition écologique / ANIL — Licence Ouverte 2.0. Retrieved in October 2026.
• INSEE, API Géo (Etalab) — Licence Ouverte 2.0. Retrieved in October 2026.
• ASN / IRSN, potentiel radon des communes — Licence Ouverte 2.0. Retrieved in October 2026.
• DGFiP, impôt sur le revenu par collectivité territoriale (IRCOM) — Licence Ouverte 2.0. Retrieved in October 2026.
• Registre national d'immatriculation des copropriétés (ANAH) — Licence Ouverte 2.0. Retrieved in October 2026.
• DGFiP, fiscalité locale des particuliers — Licence Ouverte 2.0. Retrieved in October 2026.
• Sale prices: single-property sales (flats) in the streets where the register lists co-ownerships; median calculated from 10 sales or more.