British Columbia · rules and data checked October 8, 2026

Home health check for Delta

In Health Canada's 2012 survey, 0.0% of 69 homes tested in the Fraser South Health Service Delivery Area region were above the 200 Bq/m³ radon guideline; the 2024 Cross-Canada survey found 0.9% (1 in 113) of houses at or above 200 Bq/m³ for Vancouver Metro Area. Delta's January averages 4.0 °C (ECCC), with about 2 nights a year below −10 °C, when CMHC advises keeping indoor humidity near 30% to stop window condensation. British Columbia does not require carbon monoxide alarms in existing houses.

Radon, 2012 survey

0.0%

above 200 Bq/m³ (69 homes)

Radon, 2024 survey

0.9%

Vancouver Metro Area

January average

4.0 °C

2 nights a year below −10 °C

Private wells

Rare

in Delta

Home health check for Delta

Four quick checks, set up with Delta's winter temperatures and British Columbia's alarm rules. Change any value; nothing you enter leaves your browser.

Radon test result

Pre-filled with the 2024 Cross-Canada survey's average (geometric mean) for Vancouver Metro Area. Replace it with your own result from a test of at least 3 months.

17Bq/m³ (0.5 pCi/L)

Scale to 800 Bq/m³. 1 pCi/L = 37 Bq/m³.

Below the guideline of 200 Bq/m³. No action is required. Health Canada still advises keeping radon as low as reasonably achievable, and retesting after major renovations or changes to the basement.

Health Canada's lifetime lung cancer risk: for a never-smoker about 1% at low radon, 2% after lifetime exposure at 200 Bq/m³ and 5% at 800; for a smoker 12%, 17% and 30%. Only a test of 3 months or longer gives an annual average; short tests can mislead.

Winter humidity and window condensation
°C
%
Outdoor temperature

January average: ECCC 1981–2010 normals. Cold snap: NRCan's HOT2000 winter design temperature for Delta.

69%highest humidity before the glass fogs at 4.0 °C

Double glazing, clear (1970s–1990s) (U 2.86): condensation starts at about −20.1 °C outside with 40% humidity inside.

The centre of the glass stays dry at 4.0 °C. It is about 15.2 °C, above the 6.9 °C dew point. The bottom edge and frame run colder, so condensation can start there first.

Health Canada and CMHC: keep indoor humidity between 30% and 50%. Below −10 °C outside, CMHC advises about 30%; Delta averages 2 nights a year that cold.

Smoke and carbon monoxide alarms

A sleeping area is a group of bedrooms off one hallway.

Smoke alarms required by law
1
Smoke alarms for full coverage (new-home standard)
6
CO alarms recommended
2

Not required by British Columbia law in an existing house, but strongly recommended.

“Full coverage” follows the National Building Code for new homes: one on every storey including the basement, one in each bedroom and one outside each sleeping area, interconnected. CO: NRCan advises one near the furnace or other fuel-burning appliance and one in each bedroom area.

Mould: clean it yourself or call a pro?

Example values shown. 1 m² is about 10.8 sq ft.

Small: you can clean it yourself if you are healthy.

Up to three patches, each under 1 m²: clean with water and unscented dish detergent, wearing safety glasses, an N95 mask and rubber gloves (CMHC). People at risk from mould should not clean it.

Fix the moisture source first. Testing for mould types is usually unnecessary (Health Canada). You entered 2 patches, the largest about 0.5 m².

Delta at a glance

Radon surveys covering Delta
SurveyResult
Health Canada, 2012Fraser South Health Service Delivery Area, 69 homes, long-term tests0.0% above 200 Bq/m³; 0.0% above 600
Cross-Canada survey, 2024Pacific Coastal Canada (Vancouver Island, Sea-to-Sky, Sunshine Coast, northern BC coast, Lower Mainland and western Fraser Valley up to but not including Chilliwack)1.3% (1 in 75) of households at or above 200 Bq/m³; average 20.4 Bq/m³; 3.7% between 100 and 199 Bq/m³.
Cross-Canada survey, 2024Vancouver Metro Area (Vancouver CMA)0.9% (1 in 113) of houses at or above 200 Bq/m³; weighted geometric mean 17.1 Bq/m³ (unweighted 18.3); approx. 1,000-1,499 properties with data.

The 2024 survey pools long-term tests that households volunteered, so it is not a random sample, and more tests were in basements than in 2012. Health Canada's guideline: fix a home above 200 Bq/m³ within a year. Test kits cost about $30–$80 including the lab; mitigation about $2,000–$3,000.

Highest indoor humidity before windows fog (21 °C inside)
WindowAt 4.0 °CAt −4.4 °C
Single glazing with a storm windowU 2.968%56%
Double glazing, clear (1970s–1990s)U 2.8669%57%
Double glazing, low-e and argon (2000s)U 1.879%70%
ENERGY STAR (U 1.22 or better)U 1.2285%79%
Triple glazingU 1.483%76%

Centre of the glass, from the National Building Code's indoor air film and the Magnus dew point formula. January average from ECCC normals; the cold-snap column is NRCan's winter design temperature. Window edges fog sooner, so follow CMHC: about 30% humidity below −10 °C, which Delta sees on about 2 nights a year.

Smoke alarms in British Columbia

BC Fire Code 2024 = NFC 2020 plus a BC Schedule; the Schedule does not change Article 2.1.3.3, so the NFC rule applies: alarms in each dwelling unit between sleeping areas and the rest of the home (hallway), battery alarms permitted.

Existing homes must have them: Yes · Every storey: Not confirmed · In each bedroom: No · Interconnected: No

Law: British Columbia Fire Code 2024 (Ministerial Order FSA 2023 1; NFC 2020 as amended by the Schedule)

Official source ↗

Carbon monoxide alarms in British Columbia

B.C.'s fire-safety bulletin says: 'While carbon monoxide alarms are not mandatory in B.C., it is recommended that alarms be installed if a home has a fuel-burning appliance, fireplace or attached garage.' For new construction, BC Building Code Article 9.32.4.2 requires CO alarms in buildings with a residential occupancy that are served by or contain a fuel-burning appliance, or contain a storage garage. The 2024 BCBC keeps this requirement and applies to building permits applied for on or after 2024-03-08. Locally, the City of Vancouver's Fire By-law requires CO alarms in every dwelling unit, new or older, that has an attached garage or a fuel-fired appliance, or shares a wall or floor with a parking garage or a service room containing a fuel-fired appliance.

Official source ↗

Well water in Delta

Delta's municipal system (Metro Vancouver water) serves over 100,000 residents and businesses through a 610 km network, so private drinking-water wells are uncommon.

  • Bacteria: At least once a year, and right away if clarity, colour or taste changes
  • Chemistry: When the well is completed and annually after that

British Columbia source 1 ↗

Radon help in British Columbia

New homes: Yes. The BC Building Code 2024 (building permits applied for on or after Mar 8, 2024) requires a rough-in for a subfloor depressurization system (radon rough-in) in all new Part 9 houses province-wide. It removed the earlier exemption for lower-radon areas (Information Bulletin B24-03-R).

Test kits: BC Lung Foundation runs a Radon Detector Library Lending Program with many BC library systems (free with a library card) and funds free kit distributions through local governments in Take Action on Radon's 100 Radon Test Kit Challenge (most recently listed for Fall 2024). Long-term kits are sold via BC Lung.

Other help: The BC Centre for Disease Control publishes an interactive BC Radon Map of test results by area. Lungs Matter mitigation aid (up to $1,500) is available to eligible households (BC income cap $102,500).

Find a C-NRPP certified measurement or mitigation professional at c-nrpp.ca. Data checked October 8, 2026.

Common questions in Delta

How common is radon in Delta?

Health Canada's 2012 survey found 0.0% of 69 homes tested in the Fraser South Health Service Delivery Area region at or above 200 Bq/m³. The 2024 Cross-Canada survey, which pools tests that households volunteered, reports 0.9% (1 in 113) of houses at or above 200 Bq/m³ for Vancouver Metro Area. Neighbouring houses can differ a lot, so the only way to know is a long-term test of at least 3 months, ideally in the heating season.

What indoor humidity should I keep in winter in Delta?

Health Canada and CMHC advise 30% to 50%, and CMHC says to keep it at about 30% when it is below −10 °C outside (as low as 25% in extreme cold). Delta averages 2 nights a year below −10 °C. At the January average of 4.0 °C, clear double-glazed windows start to fog at about 69% humidity at the centre of the glass, and at about 57% in a cold snap of −4.4 °C; the edges fog sooner.

How many smoke alarms does a house need in British Columbia?

BC Fire Code 2024 = NFC 2020 plus a BC Schedule; the Schedule does not change Article 2.1.3.3, so the NFC rule applies: alarms in each dwelling unit between sleeping areas and the rest of the home (hallway), battery alarms permitted. New homes built to the National Building Code need hardwired, interconnected alarms on every storey and in every bedroom, which is the standard we recommend for full coverage.

Are carbon monoxide alarms required in British Columbia?

B.C.'s fire-safety bulletin says: 'While carbon monoxide alarms are not mandatory in B.C., it is recommended that alarms be installed if a home has a fuel-burning appliance, fireplace or attached garage.' For new construction, BC Building Code Article 9.32.4.2 requires CO alarms in buildings with a residential occupancy that are served by or contain a fuel-burning appliance, or contain a storage garage. The 2024 BCBC keeps this requirement and applies to building permits applied for on or after 2024-03-08. Locally, the City of Vancouver's Fire By-law req

How often should I test my well water in British Columbia?

Bacteria: At least once a year, and right away if clarity, colour or taste changes. Chemistry: When the well is completed and annually after that. Delta's municipal system (Metro Vancouver water) serves over 100,000 residents and businesses through a 610 km network, so private drinking-water wells are uncommon.

How we calculate this

Radon

1 pCi/L = 37 Bq/m³ (Health Canada). The Canadian guideline is 200 Bq/m³; above it Health Canada recommends fixing your home within 1 year, sooner the higher the level. Only a long-term test (at least 3 months, ideally in the heating season) tells you your annual average.

Window condensation

glass temperature = indoor − U × (indoor − outdoor) ÷ 8.33

8.33 W/m²·°C is the indoor air film from the National Building Code (RSI 0.12). The dew point comes from the Magnus formula the US National Weather Service publishes; condensation forms when the glass is colder than the dew point. These are centre-of-glass figures: the bottom edge and metal frames run colder, which is why we show CMHC's simpler rule beside them (30% indoor humidity when it is below −10 °C outside, as low as 25% in extreme cold).

Smoke and CO alarms

“Required by law” applies your province's fire code to the layout you enter. “Recommended” is the new-home standard in the National Building Code (an alarm on every storey, in every bedroom and outside sleeping areas) and NRCan's CO advice (one near the furnace or other fuel-burning appliance and one in each bedroom area). Municipal by-laws can add to provincial rules.

Well water and mould

Testing frequencies and lab fees are the ones your province publishes. Mould size categories are Health Canada's and CMHC's: up to three patches each under 1 m² can be cleaned by a healthy homeowner; more than 3 m² needs a professional.

More for Delta

Heating and hot water costs in DeltaWhat heating, hot water and air conditioning cost at your local prices, and what each heating system would cost instead.Upgrade payback in DeltaSavings, rebates and payback for attic, wall and basement insulation, windows, air sealing and thermostat setbacks.Appliance running costs in DeltaWhat your fridge, dryer, freezer and other appliances cost to run at your local electricity price, and what a newer model saves.
Build your upgrade plan → All home services in Delta Radon testing in DeltaCarbon monoxide testing in DeltaWell water testing in DeltaMould testing in DeltaVentilation assessments in Delta British Columbia rebates and programs

Sources

Prices and programs checked October 8, 2026. Climate: NRCan HOT2000 (Vancouver International) for heating and ECCC 1981–2010 normals (Richmond Nature Park) for cooling and temperatures.

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