£1000 a week would be £52,000 a year profit, by the time you've added in expences you'll be over the vat threshold and be charging vat. If you wanted to grow it fast you couldn't be much more expensive that the competition so you'll have to swallow the vat in the average charge round your area.
You'll probably have to turn over £100k - £20k vat, £30k expenses / wages, £50k profit.
Say your average area is £10-£15 per household that would be
£8,000 4weekly turnover / £10 ave would be 800 customers cleaning every 4weeks
Or
£8000 4weekly turnover / £15 ave would be 533 customers cleaning every 4weeks
It could be possible just need hard work and determination.
(Don't hold me to any figures just quickly worked out)