What is pre-spray and why is it important?

Pre-spray is a cleaning solution applied to carpet before extraction cleaning. It breaks down and loosens soil, grease and stains during a dwell period, making the extraction pass much more effective. Skipping pre-spray significantly reduces cleaning results on anything other than lightly soiled carpets.

How much pre-spray per square metre?

Application rates vary by soil level: 30 ml/m² for light soiling, 50 ml/m² for moderate, 80 ml/m² for heavy, and up to 120 ml/m² for very heavy soiling. The goal is to dampen the carpet fibre without saturating the backing.

How long should pre-spray dwell?

Dwell time depends on soil level: 3-5 minutes for light to moderate soiling, 10 minutes for heavy soiling, and up to 15 minutes for very heavy or greasy soiling. Do not let the pre-spray dry on the carpet before extraction. On large areas, apply in sections.

Should I agitate pre-spray into the carpet?

Yes, agitation with a carpet rake, bonnet pad or counter-rotating brush machine helps the pre-spray penetrate deeper into the fibres and break up compacted soil. This is especially important on heavily soiled or high-traffic areas.

CleanCalcs

Pre-Spray Volume Calculator

Work out the correct volume of pre-spray solution for a given carpet area.

Carpet Area

Total carpet area to pre-spray

Soil Level

Dilution Ratio (1:X)

Check product label

Concentrate Cost per Litre (optional)

Leave blank to skip

How We Calculate This

This calculator estimates pre-spray volume based on carpet area and soil level, then splits the total into concentrate and water based on your dilution ratio.

Application rates by soil level

Light: 30 ml/m² (3 min dwell)
Moderate: 50 ml/m² (5 min dwell)
Heavy: 80 ml/m² (10 min dwell)
Very heavy: 120 ml/m² (15 min dwell)

Formula

Total solution = area x application rate

Concentrate = total solution / (dilution ratio + 1)

Water = total solution - concentrate

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities and timings for your specific situation.